sqlite - Database format for macOS
File Juicer can dump sqlite database files to text files. Since the sqlite format is built into macOS, it will become used in many situations.
One example is Quick Ceph Studios, and app for dentists. The QC2 files are SQlite based and contain JPEG images along with extra data about the photos.
An other use for SQLite is Apple Mail where the index of all received email is stored in sqlite3 format, but the email and attachments are not.
File Juicer identifies sqlite files by their content and not the sqlite extension.
To dig out data from sqlite 3 databases, you can take a look at the sqlite3 site