Regular stacks, named and pinned
The people you queue with are grouped automatically, can be named, and read as a single record across every match they played together.
Stacks you play with regularly are detected from the matches you have uploaded and grouped on their own. You can name one, pin it, and read the whole group as a single record.
Named stacks carry through to the match page: a side that is a stack you have named opens under that name rather than as five separate agents.
Per-map setups are grouped the same way, so you can see what your stack defaults to on each map rather than what each player does alone.