This is how I've observed it: Catfriend1 has long been the owner of syncthing-fork on android, which was fork of the official client syncthing-android. It had extra features around Android that were lacking in the official client (e.g sync windows to reduce battery usage).

When google locked down on file apis a year or so ago, the official syncthing-android pulled out of google play, but syncthing-fork stuck around in fdroid as the fork was for personal purposes, and they were using fdroid for distribution in the first place.

This change in ownership is new to me, but I'm also not surprised it happened as syncthing-fork was always a personal project.