[Edit: The GitHub repos are called "syncthing-android". The Android apps are called "Syncthing-Fork" or "Syncthing-Fork Wrapper", which adds to the confusion.]
If I recall, there used to be a syncthing-android app on Google PlayStore. That was discontinued by @imsodin in Oct 2024 (https://forum.syncthing.net/t/discontinuing-syncthing-androi...).
There was a version of sycnthing-android on F-Droid. I don't remember who maintained that. I have version 1.30.0.4 installed. But I cannot find any information about that version anymore.
The current version on F-Droid is 2.0.12.1. That seems to be maintained by a fellow named @researchxxl. Apparently @researchxxl claims to have inherited the source code and signing keys from a person named @Catfriend1 (Not sure who that is, the maintainer of version 1.30.0.4?)
There is another fellow named @nel0x who seems to be maintaining a different version of synchthing-android? (Edit: Here it is, https://github.com/nel0x/syncthing-android, which says that it is a fork of the one maintained by @Catfriend1).
Looks like the original repo of syncthing-android, (https://github.com/Catfriend1/syncthing-android), which was maintained by @Catfriend1, now redirects to the one maintained by @researchxxl (https://github.com/researchxxl/syncthing-android).
The problem seems to be that no one in the syncthing community knows who @researchxxl is. The account was created only 3 weeks ago. There was no communication about how the transfer took place. Was the transfer actually authorized? Did @Catfriend1 get hacked? People are worried about a backdoor hijack attack similar to the XZ libary.
There's a long discussion at https://forum.syncthing.net/t/does-anyone-know-why-syncthing.... It is too long and complex for me to follow. (I tried to get an LLM to summarize that thread for me, but the output was not helpful.)
It is unclear what sycnthing-android users are supposed to do right now. I am staying at version 1.30.0.4 until things become more clear.