Some info:
006D135900.gpi - it's POI file with MSN_Airport for work MSN flight infoservice in USA. No MSN subscription - no needing in this file.
.System\SQLite\local_poi.db - your personal setting for POI building in maps if you made it (you can exclude POI from seaching or change telephone number, and other function by manual), if you delete it - will be rebuilt by unit only empty database.
.System\SQLite\mlg_history.db - file for diagnostic info (for service), if you delete it - will be rebuilt by unit only empty database.
.System\SQLite\system.db - file for system info (it have records for some setting and after deleting may be need make this setting again), if you delete it - will be need to make this settinf again. Deleting of this file often help to solve problem with wrong setting.

D*.G2S used for TRAFFIC TRENDS compability unit with corresponding version of map. But is used in case if you send info for TRAFFIC TRENDS to Garmin. In this file no personal data and it same for all device, only necessary database SSID for online wireless connecting to server?!