Don't worry about those. That's just how MySQL stores the data internally. If you read the documentation carefully you'll soon learn that you shouldn't depend on those files for backups anyway, they're likely to be in an inconsistent state if the server's running.
The best way to make a backup for small to medium-sized databases is the mysqldump
command. There's a number of options that can be applied but the most important on a busy database is --single-transaction
which produces a consistent point-in-time snapshot.
The SQL data you get from that, which can be saved to a .sql
file, is sufficient to recreate the database and is a backup.
You can restore with the mysql
command-line tool, or if you're not comfortable with that, the MySQL Workbench program.