This looks like a decent app to access the Fediverse (an opensource collection of social media websites).
The Fediverse is essentially a collection of distributed servers which are all able to connect and communicate with each other. People can run their own 'Twitter' server, that is fully controlled by them, from styling to privacy rules, and choose how it interacts with other global communities (or not).
This may be the first time you have heard of many of these, but communities are growing pretty quickly, and being opensource, the platforms are maturing extremely well.
If you want to get your toe wet…
Masterdon is akin to twitter
Pleroma_is twitter lite
Peertube is akin to Youtube
GNUSocial is akin to Google+
Fredica is akin to Facebook
Pixedfed is akin to Instagram
*This is a little cruel to all involved. The fediverse versions offer numerous additional functional benefits and has several shortcomings to their big name counterparts… But hopefully it gets you interested in checking it out
The app is fully open source, so you are welcome to inspect the code here:
https://framagit.org/tom79/fedilab
And you could always download it directly from f-droid if you like:
https://f-droid.org/packages/fr.gouv.etalab.mastodon/
Fedilab is always free at F-Droid.