WordPress salts are companion security key, it is cryptographic tool help to secure your WordPress site.

A WordPress salt is a random string of data that hashes the WordPress security keys.
https://ithemes.com/security/wordpress-salt/#:~:text=%20There%20are%20two%20ways%20to%20change%20your,your%20WordPress%20salts%2C%20like%20iThemes%20Security%20More%20

The first four entries are your security keys.
The last four entries are your WordPress salts.