diff --git a/README.md b/README.md
index bc74a41..7151cec 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # adb-sideload-free-apps
 
-Install free Android apps via ADB from F-Droid, GitHub Releases, GitLab Releases, or Codeberg Releases.
+Install free Android apps via ADB from F-Droid, GitHub Releases, GitLab Releases, Codeberg Releases, or generic HTTPS pages.
 
 ## Requirements
 
@@ -39,11 +39,18 @@ See `config.example.toml`. Supported sources:
 | `github` | `url` (repository)            |
 | `gitlab` | `url` (projet)                |
 | `codeberg` | `url` (repository Codeberg) |
+| `generic` | `url`, `asset_pattern` (HTTPS page or directory) |
 
 Every application also requires `name` and `package`. For GitHub, GitLab, and Codeberg,
 set `asset_pattern` when a release contains more than one suitable APK. Debug,
 test and unsigned APKs are rejected by default.
 
+The `generic` source follows HTTPS anchor links from `url`. Use ordered
+`intermediate_patterns` to navigate directories; when several links match, a
+pattern with numeric capture groups selects the greatest numeric tuple.
+`asset_pattern` is required and must match exactly one final APK. Optional
+`headers` and `sha256` are supported; header values are never logged.
+
 `aapt2` is used to validate the APK package ID before installation, with
 `aapt` as a fallback for older Android SDK Build Tools. At least one of them
 must be available in `PATH`. The script refuses to install an APK when neither
diff --git a/config.example.toml b/config.example.toml
index 6108538..67bbb8a 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -55,3 +55,17 @@ url = "https://f-droid.org/packages/org.mozilla.fennec_fdroid/"
 # package = "app.fedilab.android"
 # url = "https://codeberg.org/tom79/Fedilab"
 # asset_pattern = "^Fedilab-Google-.*\\.apk$"
+
+# --- Generic HTTPS page or directory ---
+# Follow anchor links through directories, then select exactly one APK.
+# intermediate_patterns are optional and applied in order to URL path components.
+
+# [[apps]]
+# name = "Firefox"
+# source = "generic"
+# package = "org.mozilla.firefox"
+# url = "https://download.example.org/releases/"
+# intermediate_patterns = ["(?:[0-9]+\\.)+[0-9]+/$", "android/$"]
+# asset_pattern = "^firefox-.*\\.apk$"
+# headers = { Accept = "text/html" }
+# sha256 = "0000000000000000000000000000000000000000000000000000000000000000"
diff --git a/pyproject.toml b/pyproject.toml
index 81c424f..0a1859c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,7 @@
 [project]
 name = "adb-sideload-free-apps"
 version = "0.1.0"
-description = "Install free Android apps via ADB from F-Droid, GitHub, GitLab, or Codeberg"
+description = "Install free Android apps via ADB from F-Droid, GitHub, GitLab, Codeberg, or generic HTTPS pages"
 requires-python = ">=3.11"
 license = { text = "MIT" }
 readme = "README.md"
diff --git a/src/sideload.py b/src/sideload.py
index 157a8c0..a0459d3 100644
--- a/src/sideload.py
+++ b/src/sideload.py
@@ -1,4 +1,4 @@
-"""ADB Sideload Free Apps — install free Android apps from F-Droid, GitHub, GitLab, or Codeberg via ADB."""
+"""ADB Sideload Free Apps — install free Android apps from release APIs or generic HTTPS pages via ADB."""
 
 from __future__ import annotations
 
@@ -13,6 +13,7 @@ import urllib.error
 import urllib.parse
 import urllib.request
 from dataclasses import dataclass
+from html.parser import HTMLParser
 from pathlib import Path
 
 if sys.version_info >= (3, 11):
@@ -79,6 +80,8 @@ class Config:
                 raise ValueError("each app requires name and package")
             if app.source not in SOURCE_REGISTRY:
                 raise ValueError(f"unknown source type '{app.source}'")
+            if app.source == "generic":
+                _validate_generic_config(app)
             pattern = app.config.get("asset_pattern")
             if pattern:
                 try:
@@ -129,18 +132,49 @@ def _make_apk_stem(release: ReleaseInfo) -> str:
     return f"{release.app_entry.app_id}_{release.version}".replace("/", "_")
 
 
-def _atomic_download(url: str, dest: Path) -> Path:
+def _atomic_download(
+    url: str,
+    dest: Path,
+    extra_headers: dict[str, str] | None = None,
+    *,
+    conditional_headers: dict[str, str] | None = None,
+    same_origin: bool = False,
+    return_metadata: bool = False,
+) -> Path | tuple[Path | None, str, dict[str, str], int]:
     parsed = urllib.parse.urlparse(url)
     if parsed.scheme != "https":
         raise ValueError(f"only HTTPS downloads are allowed: {url}")
     dest.parent.mkdir(parents=True, exist_ok=True)
     tmp = dest.with_suffix(dest.suffix + ".tmp")
     try:
-        request = urllib.request.Request(url, headers={"User-Agent": "adb-sideload/0.1"})
-        with urllib.request.urlopen(request, timeout=30) as resp:
+        headers = dict(extra_headers or {})
+        if conditional_headers:
+            headers.update(conditional_headers)
+        headers["User-Agent"] = "adb-sideload/0.1"
+        request = urllib.request.Request(url, headers=headers)
+        opener = _generic_opener(url if same_origin else None, same_origin=same_origin)
+        with opener.open(request, timeout=30) as resp:
+            final_url = resp.geturl()
+            if not isinstance(final_url, str):
+                final_url = url
+            if urllib.parse.urlsplit(final_url).scheme != "https":
+                raise ValueError("HTTPS download redirected to a non-HTTPS URL")
+            response_headers = dict(resp.headers.items())
+            status = resp.getcode() or 200
+            if status == 304:
+                if return_metadata:
+                    return None, final_url, response_headers, status
+                raise ValueError("received HTTP 304 without a reusable cache entry")
             with tmp.open("wb") as fh:
                 shutil.copyfileobj(resp, fh)
         tmp.rename(dest)
+        if return_metadata:
+            return dest, final_url, response_headers, status
+    except urllib.error.HTTPError as exc:
+        if exc.code == 304 and return_metadata:
+            return None, url, dict(exc.headers.items()), 304
+        tmp.unlink(missing_ok=True)
+        raise
     except BaseException:
         tmp.unlink(missing_ok=True)
         raise
@@ -170,10 +204,287 @@ def _http_get(url: str, extra_headers: dict | None = None) -> bytes:
             return resp.read()
     except urllib.error.HTTPError as exc:
         raise RuntimeError(f"HTTP {exc.code} fetching {url}") from exc
+    except urllib.error.URLError as exc:
+            raise RuntimeError(f"network error fetching {url}: {exc.reason}") from exc
+
+
+def _generic_http_get(url: str, headers: dict[str, str]) -> bytes:
+    body, _, _, _ = _generic_fetch(url, headers)
+    return body
+
+
+def _same_origin(first_url: str, second_url: str) -> bool:
+    first = urllib.parse.urlsplit(first_url)
+    second = urllib.parse.urlsplit(second_url)
+    first_port = first.port or 443
+    second_port = second.port or 443
+    return (
+        first.scheme == second.scheme == "https"
+        and (first.hostname or "").lower() == (second.hostname or "").lower()
+        and first_port == second_port
+    )
+
+
+class _HttpsOnlyRedirectHandler(urllib.request.HTTPRedirectHandler):
+    def __init__(self, origin_url: str | None = None, same_origin: bool = False):
+        super().__init__()
+        self.origin_url = origin_url
+        self.same_origin = same_origin
+
+    def redirect_request(self, req, fp, code, msg, newurl, headers):
+        if urllib.parse.urlsplit(newurl).scheme != "https":
+            raise ValueError("generic HTTPS request redirected to a non-HTTPS URL")
+        if self.same_origin and self.origin_url and not _same_origin(self.origin_url, newurl):
+            raise ValueError("generic HTTPS redirect changed origin")
+        # Keep configured headers on each allowed redirect. The source is
+        # explicitly configured by the user, so this also supports CDN hops.
+        redirected = urllib.request.Request(
+            newurl,
+            headers=dict(req.header_items()),
+            origin_req_host=req.origin_req_host,
+            unverifiable=True,
+            method=req.get_method(),
+        )
+        return redirected
+
+
+def _generic_opener(origin_url: str | None = None, *, same_origin: bool = True):
+    return urllib.request.build_opener(
+        _HttpsOnlyRedirectHandler(origin_url, same_origin=same_origin)
+    )
+
+
+def _generic_fetch(
+    url: str, headers: dict[str, str], *, conditional: dict[str, str] | None = None
+) -> tuple[bytes, str, dict[str, str], int]:
+    if urllib.parse.urlsplit(url).scheme != "https":
+        raise ValueError("generic source accepts HTTPS URLs only")
+    request_headers = dict(headers)
+    if conditional:
+        request_headers.update(conditional)
+    request_headers["User-Agent"] = "adb-sideload/0.1"
+    try:
+        req = urllib.request.Request(url, headers=request_headers)
+        with _generic_opener(url, same_origin=True).open(req, timeout=30) as resp:
+            final_url = resp.geturl()
+            if not isinstance(final_url, str):
+                final_url = url
+            if urllib.parse.urlsplit(final_url).scheme != "https":
+                raise ValueError("generic HTTPS request redirected to a non-HTTPS URL")
+            status = resp.getcode() or 200
+            return resp.read(), final_url, dict(resp.headers.items()), status
+    except urllib.error.HTTPError as exc:
+        if exc.code == 304:
+            return b"", url, dict(exc.headers.items()), 304
+        raise RuntimeError(f"HTTP {exc.code} fetching {url}") from exc
     except urllib.error.URLError as exc:
         raise RuntimeError(f"network error fetching {url}: {exc.reason}") from exc
 
 
+class _AnchorParser(HTMLParser):
+    def __init__(self):
+        super().__init__(convert_charrefs=True)
+        self.hrefs: list[str] = []
+
+    def handle_starttag(self, tag: str, attrs: list[tuple[str, str | None]]) -> None:
+        if tag.lower() != "a":
+            return
+        href = dict(attrs).get("href")
+        if href:
+            self.hrefs.append(href)
+
+
+def _anchor_urls(page_url: str, body: bytes) -> list[str]:
+    parser = _AnchorParser()
+    parser.feed(body.decode("utf-8", errors="replace"))
+    urls = []
+    for href in parser.hrefs:
+        resolved = urllib.parse.urljoin(page_url, href)
+        if urllib.parse.urlsplit(resolved).scheme == "https":
+            urls.append(resolved)
+    return urls
+
+
+def _decoded_path_component(url: str) -> str:
+    path = urllib.parse.unquote(urllib.parse.urlsplit(url).path)
+    return path.rsplit("/", 1)[-1] if not path.endswith("/") else path.rsplit("/", 2)[-2] + "/"
+
+
+def _validate_generic_config(app: AppEntry) -> None:
+    url = app.config.get("url")
+    parsed = urllib.parse.urlsplit(url) if isinstance(url, str) else None
+    if not parsed or parsed.scheme != "https" or not parsed.netloc:
+        raise ValueError(f"url must be an absolute HTTPS URL for {app.name}")
+    pattern = app.config.get("asset_pattern")
+    if not isinstance(pattern, str) or not pattern:
+        raise ValueError(f"asset_pattern is required for generic source '{app.name}'")
+    try:
+        re.compile(pattern)
+    except re.error as exc:
+        raise ValueError(f"invalid asset_pattern for {app.name}: {exc}") from exc
+    intermediates = app.config.get("intermediate_patterns", [])
+    if not isinstance(intermediates, list) or not all(isinstance(p, str) for p in intermediates):
+        raise ValueError(f"intermediate_patterns must be a list of strings for {app.name}")
+    for intermediate in intermediates:
+        try:
+            re.compile(intermediate)
+        except re.error as exc:
+            raise ValueError(f"invalid intermediate_patterns for {app.name}: {exc}") from exc
+    headers = app.config.get("headers", {})
+    if not isinstance(headers, dict) or not all(
+        isinstance(k, str) and isinstance(v, str) for k, v in headers.items()
+    ):
+        raise ValueError(f"headers must be a mapping of strings for {app.name}")
+    sha256 = app.config.get("sha256")
+    if sha256 is not None and (
+        not isinstance(sha256, str) or not re.fullmatch(r"[0-9a-fA-F]{64}", sha256)
+    ):
+        raise ValueError(f"sha256 must be exactly 64 hexadecimal characters for {app.name}")
+
+
+# ── generic HTTPS HTML source ──────────────────────────────────────────────────
+
+
+class GenericSource:
+    def __init__(self, app_entry: AppEntry):
+        _validate_generic_config(app_entry)
+        self.app_entry = app_entry
+        self.start_url = app_entry.config["url"]
+        self.asset_regex = re.compile(app_entry.config["asset_pattern"])
+        self.intermediate_regexes = [
+            re.compile(pattern)
+            for pattern in app_entry.config.get("intermediate_patterns", [])
+        ]
+        self.headers = dict(app_entry.config.get("headers", {}))
+
+    def _links(self, page_url: str) -> tuple[str, list[str]]:
+        body, final_url, _, _ = _generic_fetch(page_url, self.headers)
+        return final_url, _anchor_urls(final_url, body)
+
+    def _choose_intermediate(self, links: list[str], regex: re.Pattern) -> str:
+        matches = []
+        seen = set()
+        for link in links:
+            if link in seen:
+                continue
+            seen.add(link)
+            match = regex.fullmatch(_decoded_path_component(link))
+            if match:
+                matches.append((link, match))
+        if not matches:
+            raise ValueError(
+                f"no intermediate link matches pattern for {self.app_entry.name}"
+            )
+        if len(matches) == 1:
+            return matches[0][0]
+        group_count = len(matches[0][1].groups())
+        numeric = []
+        if group_count:
+            try:
+                for link, match in matches:
+                    if len(match.groups()) != group_count:
+                        raise ValueError
+                    numeric.append((tuple(int(value) for value in match.groups()), link))
+            except (TypeError, ValueError):
+                numeric = []
+        if not numeric:
+            raise ValueError("multiple intermediate links match; make the pattern more precise")
+        greatest = max(item[0] for item in numeric)
+        winners = [link for values, link in numeric if values == greatest]
+        if len(winners) != 1:
+            raise ValueError("multiple intermediate links have the same numeric version")
+        return winners[0]
+
+    def get_latest_release(self) -> ReleaseInfo:
+        page_url = self.start_url
+        for regex in self.intermediate_regexes:
+            page_url, links = self._links(page_url)
+            page_url = self._choose_intermediate(links, regex)
+
+        assets = []
+        page_url, links = self._links(page_url)
+        for link in links:
+            filename = _decoded_path_component(link)
+            if filename.endswith("/"):
+                continue
+            if not filename.lower().endswith(".apk"):
+                continue
+            if not self.asset_regex.fullmatch(filename):
+                continue
+            if re.search(r"(?i)(debug|test|unsigned)", filename):
+                continue
+            assets.append((filename, link))
+        if not assets:
+            raise ValueError(f"no APK asset matches for {self.app_entry.name}")
+        if len(assets) > 1:
+            raise ValueError("multiple APK assets match; set asset_pattern more precisely")
+        filename, download_url = assets[0]
+        return ReleaseInfo(
+            app_entry=self.app_entry,
+            version=filename,
+            download_url=download_url,
+            expected_sha256=self.app_entry.config.get("sha256"),
+        )
+
+    def download_apk(self, release: ReleaseInfo, cache: DownloadCache) -> Path:
+        if release.expected_sha256:
+            cached = cache.find_cached(release.app_entry.app_id, release.expected_sha256)
+            if cached:
+                return cached
+        staging_dir = cache.root / release.app_entry.app_id
+        staging_dir.mkdir(parents=True, exist_ok=True)
+        metadata_path = staging_dir / "generic-cache.json"
+        metadata = {}
+        if not release.expected_sha256 and metadata_path.is_file():
+            try:
+                metadata = json.loads(metadata_path.read_text())
+            except (OSError, ValueError):
+                metadata = {}
+        cached = None
+        if not release.expected_sha256 and metadata.get("url") == release.download_url:
+            candidate = cache.cached_path(release.app_entry.app_id, metadata.get("sha256", ""))
+            if candidate.is_file() and _sha256_file(candidate) == metadata.get("sha256"):
+                cached = candidate
+        conditional = {} if cached else None
+        if cached and metadata.get("ETag"):
+            conditional["If-None-Match"] = metadata["ETag"]
+        if cached and metadata.get("Last-Modified"):
+            conditional["If-Modified-Since"] = metadata["Last-Modified"]
+        staging = None
+        try:
+            downloaded, _, response_headers, status = _atomic_download(
+                release.download_url,
+                staging_dir / "generic-download.apk",
+                self.headers,
+                conditional_headers=conditional,
+                same_origin=True,
+                return_metadata=True,
+            )
+            if status == 304 and cached:
+                return cached
+            if status == 304 or downloaded is None:
+                raise ValueError("received HTTP 304 without a reusable cache entry")
+            staging = downloaded
+            actual = _sha256_file(staging)
+            if release.expected_sha256 and actual.lower() != release.expected_sha256.lower():
+                raise ValueError(f"SHA-256 mismatch for {release.app_entry.name}")
+            result = cache.store(release.app_entry.app_id, staging, actual)
+            if not release.expected_sha256:
+                new_metadata = {
+                    "url": release.download_url,
+                    "sha256": actual,
+                    "ETag": response_headers.get("ETag", ""),
+                    "Last-Modified": response_headers.get("Last-Modified", ""),
+                }
+                tmp_metadata = metadata_path.with_suffix(".tmp")
+                tmp_metadata.write_text(json.dumps(new_metadata))
+                tmp_metadata.replace(metadata_path)
+            return result
+        finally:
+            if staging is not None:
+                staging.unlink(missing_ok=True)
+
+
 # ── download cache ────────────────────────────────────────────────────────────
 
 
@@ -612,14 +923,15 @@ SOURCE_REGISTRY = {
     "github": GitHubSource,
     "gitlab": GitLabSource,
     "codeberg": CodebergSource,
+    "generic": GenericSource,
 }
 
 
-def _make_source(app: AppEntry) -> FdroidSource | GitHubSource | GitLabSource | CodebergSource:
+def _make_source(app: AppEntry) -> FdroidSource | GitHubSource | GitLabSource | CodebergSource | GenericSource:
     cls = SOURCE_REGISTRY.get(app.source)
     if cls is None:
         raise ValueError(
-            f"unknown source type '{app.source}'. Use fdroid, github, gitlab, or codeberg"
+            f"unknown source type '{app.source}'. Use fdroid, github, gitlab, codeberg, or generic"
         )
     return cls(app)
 
@@ -732,7 +1044,7 @@ def sideload(
 def build_parser() -> argparse.ArgumentParser:
     p = argparse.ArgumentParser(
         prog="sideload",
-        description="Install free Android apps via ADB from F-Droid, GitHub or GitLab.",
+        description="Install free Android apps via ADB from F-Droid, GitHub, GitLab, Codeberg, or generic HTTPS pages.",
     )
     p.add_argument(
         "app", nargs="?", help="app name to install (omit for interactive selection)"
diff --git a/tests/test_sideload.py b/tests/test_sideload.py
index 8e627a3..51c91de 100644
--- a/tests/test_sideload.py
+++ b/tests/test_sideload.py
@@ -9,6 +9,7 @@ import subprocess
 import sys
 import urllib.error
 import urllib.request
+from contextlib import contextmanager
 from pathlib import Path
 from unittest import mock
 
@@ -43,6 +44,22 @@ def _mock_urlopen_response(data: bytes):
     return m
 
 
+def _generic_response(data: str | bytes, url: str):
+    response = _mock_urlopen_response(data.encode() if isinstance(data, str) else data)
+    response.geturl.return_value = url
+    return response
+
+
+@contextmanager
+def _mock_download_opener(response=None, *, error=None):
+    with mock.patch("sideload._generic_opener") as opener_factory:
+        if error is not None:
+            opener_factory.return_value.open.side_effect = error
+        else:
+            opener_factory.return_value.open.return_value = response
+        yield
+
+
 # ── fixtures ──────────────────────────────────────────────────────────────────
 
 
@@ -212,6 +229,20 @@ asset_pattern = ".*\\\\.apk$"
         assert cfg.apps[0].app_id == "org.schabi.newpipe"
         assert cfg.apps[0].config["url"].startswith("https://github.com/")
 
+    def test_generic_requires_https_url_and_asset_pattern(self, tmp_path: Path):
+        p = _write_config(
+            tmp_path / "cfg.toml",
+            '[[apps]]\nname="X"\nsource="generic"\npackage="x"\nurl="http://example.test/"\nasset_pattern=".*\\\\.apk"',
+        )
+        with pytest.raises(ValueError, match="absolute HTTPS"):
+            sideload.Config.from_file(p)
+        p.write_text(
+            '[[apps]]\nname="X"\nsource="generic"\npackage="x"\n'
+            'url="https://example.test/"\nasset_pattern=".*\\\\.apk"\nsha256="not-a-sha"'
+        )
+        with pytest.raises(ValueError, match="64 hexadecimal"):
+            sideload.Config.from_file(p)
+
 
 # ── DownloadCache tests ───────────────────────────────────────────────────────
 
@@ -375,7 +406,7 @@ class TestFdroidSource:
             expected_sha256=wrong_sha,
         )
         mock_resp = _mock_urlopen_response(apk_data)
-        with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+        with _mock_download_opener(mock_resp):
             with pytest.raises(ValueError, match="SHA-256 mismatch"):
                 source.download_apk(release, cache)
 
@@ -435,7 +466,7 @@ class TestGitHubSource:
         )
         apk_data = b"github-apk-content"
         mock_resp = _mock_urlopen_response(apk_data)
-        with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+        with _mock_download_opener(mock_resp):
             result = source.download_apk(release, cache)
         assert result.is_file()
         assert result.read_bytes() == apk_data
@@ -581,7 +612,7 @@ class TestGitLabSource:
         )
         apk_data = b"gitlab-apk-content"
         mock_resp = _mock_urlopen_response(apk_data)
-        with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+        with _mock_download_opener(mock_resp):
             result = source.download_apk(release, cache)
         assert result.is_file()
         assert result.read_bytes() == apk_data
@@ -590,6 +621,148 @@ class TestGitLabSource:
 # ── ApkValidator tests ────────────────────────────────────────────────────────
 
 
+class TestGenericSource:
+    def _entry(self, **config):
+        return sideload.AppEntry(
+            name="Firefox", source="generic", app_id="org.mozilla.firefox",
+            config={
+                "url": "https://downloads.example/releases/",
+                "intermediate_patterns": [r"(\d+)\/$", "android/$"],
+                "asset_pattern": r"^fenix-.*\.apk$",
+                **config,
+            },
+        )
+
+    def test_directory_navigation_and_numeric_version_selection(self):
+        entry = self._entry()
+        pages = [
+            _generic_response('<a href="1/">1</a><a href="10/">10</a><a href="http://bad/">bad</a>', entry.config["url"]),
+            _generic_response('<a href="android/">android</a>', "https://downloads.example/releases/10/"),
+            _generic_response('<a href="fenix-1.multi.android-arm64-v8a.apk?download=1">apk</a>', "https://downloads.example/releases/10/android/"),
+        ]
+        with mock.patch("sideload._generic_opener") as opener_factory:
+            opener_factory.return_value.open.side_effect = pages
+            release = sideload.GenericSource(entry).get_latest_release()
+        assert release.download_url.endswith(".apk?download=1")
+        assert release.version == "fenix-1.multi.android-arm64-v8a.apk"
+
+    def test_ambiguous_intermediate_links(self):
+        entry = self._entry(intermediate_patterns=[r"release/$"])
+        page = _generic_response('<a href="a/release/">a</a><a href="b/release/">b</a>', entry.config["url"])
+        with mock.patch("sideload._generic_opener") as opener_factory:
+            opener_factory.return_value.open.return_value = page
+            with pytest.raises(ValueError, match="multiple intermediate"):
+                sideload.GenericSource(entry).get_latest_release()
+
+    def test_excludes_debug_and_rejects_http_assets(self):
+        entry = self._entry(intermediate_patterns=[], asset_pattern=r"^good\.apk$")
+        page = _generic_response(
+            '<a href="http://downloads.example/good.apk">http</a>'
+            '<a href="good-debug.apk">debug</a><a href="good.apk">good</a>',
+            entry.config["url"],
+        )
+        with mock.patch("sideload._generic_opener") as opener_factory:
+            opener_factory.return_value.open.return_value = page
+            release = sideload.GenericSource(entry).get_latest_release()
+        assert release.download_url.endswith("good.apk")
+
+    def test_initial_http_and_network_error(self):
+        bad = self._entry(url="http://downloads.example/releases/")
+        with pytest.raises(ValueError, match="absolute HTTPS"):
+            sideload.GenericSource(bad)
+        entry = self._entry()
+        with mock.patch("sideload._generic_opener") as opener_factory:
+            opener_factory.return_value.open.side_effect = urllib.error.URLError("offline")
+            with pytest.raises(RuntimeError, match="network error"):
+                sideload.GenericSource(entry).get_latest_release()
+
+    def test_headers_are_sent_but_not_exposed(self, capsys):
+        entry = self._entry(intermediate_patterns=[], asset_pattern=r"^good\.apk$", headers={"Authorization": "secret-token"})
+        response = _generic_response('<a href="good.apk">good</a>', entry.config["url"])
+        with mock.patch("sideload._generic_opener") as opener_factory:
+            opener_factory.return_value.open.return_value = response
+            sideload.GenericSource(entry).get_latest_release()
+        request = opener_factory.return_value.open.call_args.args[0]
+        assert request.get_header("Authorization") == "secret-token"
+        captured = capsys.readouterr()
+        assert "secret-token" not in captured.out + captured.err
+
+    def test_https_redirect_is_blocked_before_following(self):
+        request = urllib.request.Request(
+            "https://downloads.example/start", headers={"Authorization": "secret-token"}
+        )
+        with pytest.raises(ValueError, match="non-HTTPS"):
+            sideload._HttpsOnlyRedirectHandler().redirect_request(
+                request, mock.Mock(), 302, "Found", "http://evil.example/", {}
+            )
+
+    def test_cross_host_redirect_is_blocked_and_same_origin_keeps_headers(self):
+        request = urllib.request.Request(
+            "https://downloads.example/start", headers={"Authorization": "secret-token"}
+        )
+        handler = sideload._HttpsOnlyRedirectHandler(
+            "https://downloads.example/start", same_origin=True
+        )
+        with pytest.raises(ValueError, match="changed origin"):
+            handler.redirect_request(
+                request, mock.Mock(), 302, "Found", "https://cdn.example/file", {}
+            )
+        redirected = handler.redirect_request(
+            request, mock.Mock(), 302, "Found", "https://downloads.example/file", {}
+        )
+        assert redirected.get_header("Authorization") == "secret-token"
+
+    def test_atomic_download_rejects_downgrade_before_response_body(self):
+        request = urllib.request.Request("https://downloads.example/file.apk")
+        handler = sideload._HttpsOnlyRedirectHandler(
+            "https://downloads.example/file.apk", same_origin=False
+        )
+        with pytest.raises(ValueError, match="non-HTTPS"):
+            handler.redirect_request(
+                request, mock.Mock(read=mock.Mock(side_effect=AssertionError)),
+                302, "Found", "http://downloads.example/file.apk", {}
+            )
+
+    def test_redirected_page_url_is_used_for_relative_links(self):
+        entry = self._entry(intermediate_patterns=[] , asset_pattern=r"^good\.apk$")
+        response = _generic_response('<a href="good.apk">good</a>', "https://cdn.example/final/")
+        with mock.patch("sideload._generic_opener") as opener_factory:
+            opener_factory.return_value.open.return_value = response
+            release = sideload.GenericSource(entry).get_latest_release()
+        assert release.download_url == "https://cdn.example/final/good.apk"
+
+    def test_generic_cache_uses_conditional_request_without_sha(self, tmp_path: Path):
+        entry = self._entry(intermediate_patterns=[] , asset_pattern=r"^good\.apk$")
+        source = sideload.GenericSource(entry)
+        release = sideload.ReleaseInfo(entry, "good.apk", "https://downloads.example/good.apk", None)
+        first = _generic_response(b"apk-content", release.download_url)
+        first.headers = {"ETag": "v1"}
+        first.getcode.return_value = 200
+        second = _generic_response(b"", release.download_url)
+        second.headers = {}
+        second.getcode.return_value = 304
+        with mock.patch("sideload._generic_opener") as opener_factory:
+            opener_factory.return_value.open.side_effect = [first, second]
+            cache = sideload.DownloadCache(tmp_path / "cache")
+            cached_first = source.download_apk(release, cache)
+            cached_second = source.download_apk(release, cache)
+        assert cached_second == cached_first
+        assert cached_second.read_bytes() == b"apk-content"
+        second_request = opener_factory.return_value.open.call_args_list[1].args[0]
+        assert second_request.get_header("If-none-match") == "v1"
+
+    def test_generic_cache_rejects_304_without_valid_cache(self, tmp_path: Path):
+        entry = self._entry(intermediate_patterns=[], asset_pattern=r"^good\.apk$")
+        release = sideload.ReleaseInfo(entry, "good.apk", "https://downloads.example/good.apk", None)
+        response = _generic_response(b"", release.download_url)
+        response.getcode.return_value = 304
+        with _mock_download_opener(response):
+            with pytest.raises(ValueError, match="304"):
+                sideload.GenericSource(entry).download_apk(
+                    release, sideload.DownloadCache(tmp_path / "cache")
+                )
+
+
 class TestApkValidator:
     def test_validate_success(self, apk_file: Path):
         validator = sideload.ApkValidator(aapt2_bin="fake-aapt2", aapt_bin="fake-aapt")
@@ -747,6 +920,13 @@ class TestMakeSource:
         s = sideload._make_source(codeberg_entry)
         assert isinstance(s, sideload.CodebergSource)
 
+    def test_generic(self):
+        entry = sideload.AppEntry(
+            name="X", source="generic", app_id="x",
+            config={"url": "https://example.test/", "asset_pattern": r"x\.apk"},
+        )
+        assert isinstance(sideload._make_source(entry), sideload.GenericSource)
+
     def test_unknown_source_raises(self):
         entry = sideload.AppEntry(name="X", source="unknown", app_id="x", config={})
         with pytest.raises(ValueError, match="unknown source type"):
@@ -783,7 +963,7 @@ class TestSideload:
         with mock.patch(
             "sideload._http_get", return_value=json.dumps(fdroid_index).encode()
         ):
-            with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+            with _mock_download_opener(mock_resp):
                 with mock.patch("sideload._run", side_effect=mock_run):
                     result = sideload.sideload(
                         app_entry, config, dry_run=True,
@@ -821,7 +1001,7 @@ class TestSideload:
         with mock.patch(
             "sideload._http_get", return_value=json.dumps(fdroid_index).encode()
         ):
-            with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+            with _mock_download_opener(mock_resp):
                 with mock.patch("sideload._run", side_effect=mock_run):
                     result = sideload.sideload(
                         app_entry, config, dry_run=True,
@@ -865,7 +1045,7 @@ class TestSideload:
         with mock.patch(
             "sideload._http_get", return_value=json.dumps(fdroid_index).encode()
         ):
-            with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+            with _mock_download_opener(mock_resp):
                 with mock.patch("sideload._run", side_effect=mock_run):
                     result = sideload.sideload(
                         app_entry, config,
@@ -910,7 +1090,7 @@ class TestSideload:
         with mock.patch(
             "sideload._http_get", return_value=json.dumps(fdroid_index).encode()
         ):
-            with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+            with _mock_download_opener(mock_resp):
                 with mock.patch("sideload._run", side_effect=mock_run):
                     result = sideload.sideload(
                         app_entry, config,
@@ -963,7 +1143,7 @@ class TestSideload:
         with mock.patch(
             "sideload._http_get", return_value=json.dumps(fdroid_index).encode()
         ):
-            with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+            with _mock_download_opener(mock_resp):
                 with mock.patch("sideload._run", side_effect=mock_run):
                     result = sideload.sideload(
                         app_entry, config,
@@ -1008,7 +1188,7 @@ class TestCLI:
         }
         mock_resp = _mock_urlopen_response(apk_data)
         with mock.patch("sideload._http_get", return_value=json.dumps(fdroid_index).encode()):
-            with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+            with _mock_download_opener(mock_resp):
                 with mock.patch("sideload._run", return_value=subprocess.CompletedProcess(
                     args=[], returncode=0, stdout="org.mozilla.fennec_fdroid\n", stderr=""
                 )):
@@ -1064,7 +1244,7 @@ class TestUtilities:
         dest = tmp_path / "sub" / "file.apk"
         data = b"downloaded-content"
         mock_resp = _mock_urlopen_response(data)
-        with mock.patch("urllib.request.urlopen", return_value=mock_resp):
+        with _mock_download_opener(mock_resp):
             result = sideload._atomic_download("https://example.com/x.apk", dest)
         assert result == dest
         assert dest.read_bytes() == data
@@ -1072,7 +1252,7 @@ class TestUtilities:
 
     def test_atomic_download_cleans_up_on_error(self, tmp_path: Path):
         dest = tmp_path / "file.apk"
-        with mock.patch("urllib.request.urlopen", side_effect=RuntimeError("fail")):
+        with _mock_download_opener(error=RuntimeError("fail")):
             with pytest.raises(RuntimeError):
                 sideload._atomic_download("https://example.com/x.apk", dest)
         assert not dest.exists()