Android regularly adds and splits permissions for new API levels. Legacy apps are handled by treating them as requesting the permission to provide a toggle for it. For example, Android 13 converted the existing toggle for disabling notifications for an app into a new POST_NOTIFICATIONS permission.
The Android Open Source Project has infrastructure for this since it's a regular part of the app sandbox and permission model improving. We add Network and Sensors permission toggles in GrapheneOS where Network is based on the existing low-level INTERNET permission and Sensors is entirely new.
Nearly all apps are unaware of these non-standard permissions just as they're unaware of new permissions added by Android before they get upgraded. Therefore, we enable them by default for compatibility but provide the ability for users to disable them at install time like the standard permissions.
For Network, apps request INTERNET, so we provide a toggle for rejecting that request in the initial app install dialog. If it's added in an upgrade, it's disabled by default. For Sensors, apps don't request it so we handle it similarly to how Android handled POST_NOTIFICATIONS for existing apps.
When Network is disabled, we act as if the network is down for compatibility. We won't run network-dependent jobs, various APIs will report it as down and we give errors matching it being down. When Sensors is disabled, sensors not covered by standard permissions give zeroed data and no events.
For usability, apps trying to use those sensors when Sensors is disabled will trigger a notification from the OS which can be disabled on a per-app basis. This informs users about what's going on so they'll know the app is either doing something sketchy or that it may actually require it.
F-Droid has an incorrect approach to installing apps which wrongly warns users about the standard Android POST_NOTIFICATIONS permission, our OTHER_SENSORS permission and previous Android permission additions/splits. They wrongly blamed GrapheneOS and didn't fix it:
They're now realizing that it happens with standard Android permissions added / split in new releases. Their approach to installing apps has been incorrect in multiple ways for many years and this is one of them. Their approach to listing which permissions are used by apps is also very incorrect.
F-Droid has a long history of denying issues including covering up serious security flaws. In some cases they eventually ship a fix but still deny it. It's a major factor in why F-Droid is not a safe or trustworthy source of apps due to major security issues not being acknowledged or addressed.
Multiple of the F-Droid developers wrongly blaming their app bug on GrapheneOS in that issue are Calyx contractors. They prioritize attacking GrapheneOS with inaccurate claims and fabricated stories about our team over fixing a bug in their app impacting both GrapheneOS and non-GrapheneOS users.
We've repeatedly brought up F-Droid not properly listing permissions or checking for them. Their understanding of Android's permission model is wrong. The way they list permissions misleads and misinforms users. It's one of many major F-Droid flaws they consistently don't acknowledge or fix.
Due to F-Droid deliberately causing friction and annoyances for GrapheneOS users, we'll be implementing a feature similar to our sandboxed Google Play compatibility layer for it. We'll resolve the deliberate issues created for GrapheneOS users ourselves and replace the info it provides about itself.
@GrapheneOS I agree with you that F-Droid is being silly, as that toast is not actionable and as you say, stock OS permission additions/splits will trigger it.
But I am surprised by how you handled it. You wrote a highly valuable technical comment on their GitLab, but for some reason added unrelated grievances to it and then copy-pasted it many times all over this GitLab issue. This is rude and unprofessional. Many projects would delete these comments and warn you, or even ban you.
