mapLayersDirectory
App-internal storage, so imported layers are private to the app and removed with it.
Where imported layer files are kept for this platform.
Imports are copied here rather than read from wherever the user picked them: the source may be a content:// the app has no lasting permission for, or a file the user later moves. The copy is what the layer list persists — the directory listing is the layer list on restart.
Alongside the desktop database, which already lives in ~/.meshtastic.