Definitions of grouping functions using Group function

[sanalytics3]

Does anyone know the exact definitions of these conditions using the “Group By” function on the front end of looker?

[sanalytics3]

I am curious the different between “is” and “contains.” Is there a field where a category can contain 1 item including another. I noticed when using the group by function it automatically says “OR” instead of and. For example…

1. Label - All orders that contain a jacket [contains] 

2. Label- Orders that contain a jacket and pants [contains] jacket + [contains] pants

However I noticed that the second bullet, when using the contains function, it automatically says jacket OR pants.