“The reason is a combination of Google making Play publishing something between hard and impossible and no active maintenance. The app saw no significant development for a long time and without Play releases I do no longer see enough benefit and/or have enough motivation to keep up the ongoing maintenance an app requires even without doing much, if any, changes.”
Yep, there’s one called syncthing-fork that’s been around quite a while I think, lemme go grab a link
Edit: https://f-droid.org/packages/com.github.catfriend1.syncthingandroid/ :)
I haven’t followed whether the project has made any comment on the upstream being discontinued, because right now I’m not using it. But if you reading this depend on syncthing, it might be worthwhile to go check, and maybe donate to help them keep it going :)