Purpose of "derived" set in _checkColumns?

The "derived" set is a group of "column names that won't prompt the user for input when updating." It isn't used anywhere except in instantiation. Is this a feature planned for the future?

Start by locating _checkColumns and inspect how the "derived" set is instantiated and whether it is referenced elsewhere. The issue does not define whether the set should be removed, documented, or made functional, so confirm the intended behavior with a maintainer before changing code; completion depends on that decision.

Written by the indexing model from the issue text.