White-list particular Jira users
In case you want to track a specific list of users (white list), you can start typing their names and select them from the search results:
Black-list particular Jira users
In case you do not want to track a specific list of users (black list), you can switch to “Exclude” and start typing their names to select them from the search results:
Include / Exclude inactive or unassigned
If you don’t want to track inactive Jira users or issues not assigned to anyone, you can switch off the showing of each option: