That is the User Directory. [The User Directory location varies because of operating system requirements. The hotlink points to the wiki page about this.] As suggested above, make a copy of the folder.
Looking at database files with a database program (like Gramps) forces an update the file. That can corrupt the file if tried with an incompatible database program. (That is why you should always work on a copy.)
Instead of the database file, let us look at some text files that will identify the version, database path and backup path. If there is recent
.gramps backup file, then importing the backup file will be the safest way to recover your Tree.
Inside the Gramps folder will be another Gramps folder with the version number as part of the name. (Like
Inside that folder is a
gramps.ini text file.
Scroll down to the section labeled [
This will include the backup path & the database path. The section (for Windows) looks like: