the page on github only has the icon and the APKs, there is no source code. Perhaps the Apache licence is only applied to the icon? I don't know... alternativeto.net marks it as proprietary
But nevertheless, I've been tinkering with infinity for lemmy and I think I will choose this as my main app for the moment.
In fact I am replying to you using infinity. I really do enjoy this app after I've finished customizing it, the settings took me more than 30 minutes because of the sheer number of combinations I had to try.
But after I finished setting up, it is a joy to use.