How do blueprint and process tags work?

Tags can be added to blueprints via the More Details drawer: 

Simply type the tag name in:

and watch as it appears underneath the blueprint title in the header:

and to processes:

The blueprint tag will appear in the blueprint library and on each process that is started using the blueprint. 

You can remove and add new tags to a process. 

A tag enables the blueprint and process to be searched and viewed by this label in the Blueprint Library and Process Tracker via the custom process view.