[btzs]

This is a similar project from Karlsruhe University:

Summary: All Privacy Friendly Apps:

- are Open Source (GPLv3) and their source code can be viewed an Github by anybody

- used minimal permissions

- do not neither tracking mechanisms nor advertisement

https://secuso.aifb.kit.edu/english/105.php

[m0shen]

The fitness apps looked exactly like what I need, but when going to the play store says they were made for an older version of Android. Visiting Github seems like they aren't actively maintained either.

[mcv]

Fork them, I guess. That remains the main big advantage of open source.

I've had closed source apps, even paid ones, disappear without a trace from my phone and tablets, presumably after an OS update. I find that an incredibly shitty thing to be subjected to. If an OS update is going break any apps, I'd like to be warned about that.

[harry8]

These are great. Get them from fdroid.