users table explanation

Hi,
I used Traccar to save device's data into the database.
Automatically, Traccar created the database.

There are some attributes in the table "users", i don't know what is the meaning of the following attributes: hashedpassword, salt, readonly and admin.

Can you please tell me what does each of these attributes mean?

Thanks

hashedpassword - hash of the user password
salt - salt used to calculate hash
readonly - not used, reserved
admin - user has administrator privileges