Let's say you have information that you want to make available to certain team members, but it's not crucial that they show that they've "completed" it.
Enter Reference subjects!
To make a subject a Reference (instead of required):
Edit the desired subject
Click the 3-dot menu and select Advanced Settings
Toggle off the "Require completion of Subject"
Doing so will add a Reference tag to the Subject. Now, any team member who has been assigned this Subject will be able to search for and access the content but they will NOT be required to complete it.
IMPORTANT: Team members who are NOT assigned to the reference subject will NOT be able to find it in search results. So, if you want someone to be able to find it, they need to be assigned to it.