Postgres view column references
PostgreSQL doesn't track which view column depends on which object. It is the view as a whole that is tracked.

But PostgreSQL tracks on which table columns (and other objects) a view depends: Each view is related to its query rewrite rule in pg_rewrite, and the query rewrite rule has a dependency on the table columns (and other objects) used in the view. These dependencies are tracked in pg_depend.

Putting the pieces of the puzzle together is straightforward, but takes a while. I have written a blog about this recently.