View all multi-column constraints?

In the "structure" view of tables, there is a column for showing constraints, but these only show the constraints for that particular row (i.e. attribute). I'm working on a database with more than a few multi-column constraints (foreign keys, mostly), which I can only identify through the "DDL" view. Is there another way to view multi-column constraints that I don't know of? I tried the "help" menu item but couldn't find any more information.
I suppose the same goes for adding multi-column constraints. Perhaps it would make sense to move the constraints down (below "Indexes", for example) and to use references where the constraints are shown now (e.g. colored links that show a symbol or the name of the constraint)?

Start by comparing the table’s “structure” view with its “DDL” view, focusing on how multi-column foreign keys and other constraints are represented. Determine the intended placement and interaction for viewing and adding these constraints; done means the relevant multi-column constraints are discoverable without relying only on the DDL view.

Written by the indexing model from the issue text.