Roles is a replacement for the existing moderator list. Instead of fixed moderators, or the far more confusing 'assigned' moderators, roles can be customised and created at will.
Existing moderator lists will now be converted to 'enrolments', using default roles created for each room. A room's 'permanent' moderators, those originally assigned by the room owner, will be enrolled to the moderators role. Enrolling additional users requires either being the room owner or having the appropriate role permission.
Currently, roles can be visually customised by giving them an icon with a colour, as well as a descriptive name. These will appear in the user list where the mod star used to be. Eventually, I'll add the ability for icons themselves to be changed, or custom icons uploaded for rooms with gold status.
This is effectively a complete re-write of the moderation functionality throughout the site. While I've tested existing functionality quite a bit, it's probably not absolutely perfect so please be sure to send some constructive feedback if things aren't working quite right.
Using the roles system
Instead of a moderator list in your room settings, use the Room Settings/Users page in the room settings. Here you can search for users by their username and assign them to existing roles.
Create and remove roles in the Room Settings/Roles page in the room settings. Default roles, moderators and everybody, can not be removed, though they can be renamed and their permissions updated.