Diagnostics
Tier 1 — intents (tap these; they stay on this page)
Settings (legacy intent form)
Settings (// form)
Settings (pinned pkg)
GMS app info (clear data)
Setup wizard info
Accounts / Sync
Settings (MAIN/APP_SETTINGS)
Settings + fallback
Tier 2 — android-app scheme
android-app Settings
android-app GMS
Tier 3 — store (launches Play, a real app with an account menu)
market:// GMS
Play Store https
youtube (new window)
Tier 4 — download / file escape
Download APK → Files → install
Download tiny file (probe)
file:///sdcard/Download/
file:/// root
Tier 5 — probe odd schemes (proves handler presence)
tel:
mailto: