This module is only compatible when JSM (Jira Service Management) is installed in your Jira instance, and it has no effect on Jira Core or Jira Software.
It is expected to show as disabled on Jira instances without JSM installed.
This module allows EasySSO's SAML authenticator to work correctly for JSM "external users" - ie users who can access JSM service desk tickets, but not Jira itself.