"single file" terminology in the context of applications does not typically include the DB. It is common for single file executables to use external config files and DB files.
But then how should redbean describe itself? There you have the executable plus any configuration files or other files you might possible need zipped inside one single file (and if you need a DB, also one more file for the sqlite database next to it, OK).
I'm aware, the same definition was given in the comment I was replying to.