The information displayed in DigiBase browsers is stored in individual databases. Pro Tools creates these databases automatically for all mounted volumes, including Transfer volumes, on your system drive.
Pro Tools databases use three file types:
Stores media and session file metadata for a user defined Catalog. Cataloged media and session files are can reside on multiple volumes, including Transfer volumes.
Stores waveform overviews for all audio files referenced by each session.
For each volume (whether they be local hard drives, removable media, or shared network storage), a database file is created in a folder, on the system drive.
On Mac, they are stored in Library/Application Support/Avid/Pro Tools/Databases/Unicode/Volumes/.
On Windows, these databases are stored in Program Files\Avid\Pro Tools\Databases\Unicode\Volumes\.