This is handled rather inconsistently in Shopware. In some but not all places, if you leave out the salutation, Shopware searches the database for the "not_specified" entry that comes with the installation and inserts it if found. If also sometimes inserts it just for display in the Administration if the real salutation reference is null, so you wouldn't even know the real value without looking directly into the database, but again, not always.

Crucially, that "not_specified" entry can be changed and deleted at will, so there's no guaranteed meaning behind it.

Also, sometimes like in the contact form the salutation is randomly required. You can delete it for addresses and the database has a default value of null, but then there is a non-configurable validator that won't let you through the checkout process if no salutation is given. And again, "given" can just mean that you set the "not_specified" salutation, which can have any meaning you assign to it.

This is an intransparent mess and should be changed. The very legality of requiring a salutation is now even in question. Just allow null values for all salutations in the application, it's already allowed in the DB structure, stop enforcing it in random places without a way to turn it off, and make the display name of a "null" salutation translatable via config.