SQLite

SQLite is an embedded, in-process SQL database that keeps its data in a single file.

SQLite file format

The SQLite file format is documented at https://sqlite.org/fileformat.html.
The format is essentially a collection of pages that form B-Trees.
While writing a whole SQL engine for querying the file might be a large task, it's quite easy to dump all rows by reading the pages.
Very useful interactive exploration of the SQLite file format: https://sqlite-internal.pages.dev/