Project file storage for Premiere Rush

I saw in a previous (and now locked ) thread asking about where the Premiere Rush project file is stored that; an adobe expert stated that Premiere Rush does not store the project data in a project file, per se.

That it is stored in a database.

Okay, can someone provide either the database file extension

I will assume that the database would contain all of the projects that have been created since that would be the point of a database versus a file, right?

Where the database is stored?

And how one can set the default location of the database. 

This would allow two valuable events to transpire

1. The user could back up the database for safeKeeping 

2. The user could insure that the database (which will grow as one does more projects ) has ample space for said growth.

A final question, is the database itself size, project, or age limited? 

I.E.  if the user do not delete a project, what would remove that project from the database

Thanks