SQLite - What are .acd, .ard and related file types? I'm using a SQLite database, and the main database file is:

Config.acd


and there are also files named:

Config.acd-shm
Config.acd-wal


What is the .acd file type, what are those variants (acd-shm, acd-wal), and why is the main file not a .db file?

I also have the following files, what are these:

Raw.ard
Raw.ard-shm
Raw.ard-wal
The -wal and -shm files are used to store data when the DB is in WAL mode.

SQLite does not require any specific file name or extension. These file names are chosen by the program that created the database.