Is Damus FOSS and if so, are there checksums available for the APK?
Discussion
Unfortunately it looks like Will hasn't update the master to current version on the Github. On the site, the version is 0.7.1 but latest on Github is 0.4.0 beta.
The binaries yes, but the code is up to date.
Latest binaries are here https://damus.io/notedeck/install/
Thanks