On the GrapheneOS forum you will see a lot of bad opinions about F-Droid, for example this:
> It doesn't matter that the app is trustworthy, because F-Droid are extremely incompetent with security and the apps you install from F-Droid are signed by F-Droid rather than the developer.
https://discuss.grapheneos.org/d/20212-f-droid-security-in-s...
https://discuss.grapheneos.org/d/18731-f-droid-vulnerability...
They also say, if you use F-Droid, at least use F-Droid Basic:
> Dont use the main F-Droid client. Android is pretty strict about SDK versions and as F-Droid targets legacy devices, it is very outdated.
https://discuss.grapheneos.org/d/11439-f-droid-vsor-droid-if...
> If the app is only available on F-Droid / third party F-Droid repo, use F-Droid Basic and use the third party repo rather than the main repo if available.
>
> If the app is available on Github then install the APK first from Github then auto-update it using Obtanium. Be sure to check the hash using AppVerifier which can be installed from Accrescent (available on the GrapheneOS app store).
https://discuss.grapheneos.org/d/16589-obtainium-f-droid-bas...
By the way, while GrapheneOS recommends Accrescent, I don't use it anymore because they can't even add apps like CoMaps, while some of the apps they actually added are proprietary.
> It doesn't matter that the app is trustworthy, because F-Droid are extremely incompetent with security and the apps you install from F-Droid are signed by F-Droid rather than the developer.
https://discuss.grapheneos.org/d/20212-f-droid-security-in-s... https://discuss.grapheneos.org/d/18731-f-droid-vulnerability...
They also say, if you use F-Droid, at least use F-Droid Basic:
> Dont use the main F-Droid client. Android is pretty strict about SDK versions and as F-Droid targets legacy devices, it is very outdated.
https://discuss.grapheneos.org/d/11439-f-droid-vsor-droid-if...
> If the app is only available on F-Droid / third party F-Droid repo, use F-Droid Basic and use the third party repo rather than the main repo if available. > > If the app is available on Github then install the APK first from Github then auto-update it using Obtanium. Be sure to check the hash using AppVerifier which can be installed from Accrescent (available on the GrapheneOS app store).
https://discuss.grapheneos.org/d/16589-obtainium-f-droid-bas...
By the way, while GrapheneOS recommends Accrescent, I don't use it anymore because they can't even add apps like CoMaps, while some of the apps they actually added are proprietary.