[sqlite] Does it matter what extension is used for SQLite database files?

Are there advantages or disadvantages to the file extension used for SQLite databases?

It seems that SQLite itself does not require a naming convention, but there might be other reasons that a particular extension would be useful or problematic - for instance, certain tools, programming languages, installers, etc. Or end user considerations.

The most common ones appear to be .sqlite, .db, and .db3.

SQLite doesn't define any particular extension for this, it's your own choice. Personally, I name them with the .sqlite extension, just so there isn't any ambiguity when I'm looking at my files later.

In distributable software, I dont want my customers mucking about in the database by themselves. The program reads and writes it all by itself. The only reason for a user to touch the DB file is to take a backup copy. Therefore I have named it whatever_records.db

The simple .db extension tells the user that it is a binary data file and that's all they have to know. Calling it .sqlite invites the interested user to open it up and mess something up!

Totally depends on your usage scenario I suppose.

Emacs expects one of db, sqlite, sqlite2 or sqlite3 in the default configuration for sql-sqlite mode.

If you have settled on a particular set of tools to access / modify your databases, I would go with whatever extension they expect you to use. This will avoid needless friction when doing development tasks.

For instance, SQLiteStudio v3.1.1 defaults to looking for files with the following extensions:

(db|sdb|sqlite|db3|s3db|sqlite3|sl3|db2|s2db|sqlite2|sl2)

If necessary for deployment your installation mechanism could rename the file if obscuring the file type seems useful to you (as some other answers have suggested). Filename requirements for development and deployment can be different.