@JingMatrix

Thanks for working on this. I pulled and tested the PR locally.

What looks good:

• https://backup.modules.lsposed.org/modules.json currently returns 200 with the expected JSON payload, while the old list endpoint https://modules.lsposed.org/modules.json returns 403 for me.
• The per-module JSON endpoint also works on the backup host, e.g. https://backup.modules.lsposed.org/module/com.luckyzyx.luckytool.json returns 200.
• ./gradlew.bat --no-daemon :app:compileDebugJavaWithJavac and :app:assembleDebug both pass locally on this branch.

One regression I noticed: RepoItemFragment changes the "open in browser" URL from https://modules.lsposed.org/module/<package> to https://backup.modules.lsposed.org/module/<package>, but the backup host appears to serve only the JSON API for module details. For example:

• https://backup.modules.lsposed.org/module/com.luckyzyx.luckytool -> 404
• https://modules.lsposed.org/module/com.luckyzyx.luckytool -> 200 HTML page
• https://backup.modules.lsposed.org/module/com.luckyzyx.luckytool.json -> 200 JSON

So it may be better to keep a separate web base URL for menu_open_in_browser, and only use the backup host for the JSON API calls.

A smaller robustness note: loadRemoteData() / loadRemoteReleases() still silently ignore non-2xx HTTP responses. That is the behavior that made the old 403 list response hard to surface in the UI. Not necessarily required to fix the current outage, but treating non-successful responses as load failures would make the repo loader less fragile next time a CDN endpoint changes.

I opened a small follow-up PR at #765 with the two adjustments mentioned above: keeping the browser URL on the public web host, and surfacing non-2xx / empty API responses as load failures.

Thanks again for the original fix and investigation here. If maintainers prefer this to stay in #747 instead, the changes should be straightforward to fold back.