AndroidX Core
Official docs outline
5 sections- Core release notes
androidx.core artifact versions.
- Android KTX
Kotlin extensions for Android APIs.
- Permissions with ContextCompat
ContextCompat.checkSelfPermission and ActivityCompat.
- Notifications
NotificationCompat and channels.
- Core splashscreen
SplashScreen API and compat library.
Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.