Display a search list of all cards related to Something?+discussion

short answer: you could get all those things, yes, but the query would have to grow more complex with each "generation" of complexity you want to cover.

Our word for this relationship is "descendant". A+B is a child of A and B. A+B+C is a child of A+B. A+B, A+B+C, and A+B+C+D are all descendants of A (and B).

something+*children will give all of the direct children (eg Something+Else, Whatever+Something) but not all the descendants/grandchildren (eg Something+Else+Status).

Its WQL query uses the "plus" directive. It would be possible to construct a WQL query to give multiple generations, but only by traversing child by child; WQL can't recurse.