I don't see the APK on the GH either but it is signed by nostr:nprofile1qqszpxr0hql8whvk6xyv5hya7yxwd4snur4hu4mg5rctz2ehekkzrvcpzamhxue69uhhyetvv9ujuurvv438xarj9e3k7mgpr9mhxue69uhkummnw3ezu7n9vfjkget99e3kcmm4vsq3yamnwvaz7tm0venxx6rpd9hzuur4vg5xqmxe on Zapstore so, possibly they upload the compiled version on Zapstore. It has a checksum on Zapstore as well, so, if you compile the app yourself you can check the values against each other to confirm the compile is legit.