Source code of the Android app Old School Companion
Play store: https://play.google.com/store/apps/details?id=com.dennyy.osrscompanion
The app isn't available on the Play Store anymore, maybe on F-droid in the future
Dropbox link: https://www.dropbox.com/s/ucly0lgbvvultd8/Old%20School%20Companion.apk?dl=0