In this post it is explained: https://www.sweethome3d.com/support/for ... 1818#55074 (about halfway in the post).
It includes examples and objects to review.

It's called chaining of deformations. There are still some limitations but with the current possibilities I created a dishwasher where the top rack can be pulled out (rail) AND a side shelf on the same rack can be turned up/down (hinge chained to the rail). The same dishwasher also has a door on a hinge not chained to the two racks inside and the bottom rack can be pulled out on its own rail. All in the same object. Such combinations are now possible.