Purpose of "Allow custom publication comment" Setting: Improve Documentation and Maybe UI?

The Allow custom publication comment feature introduced by XAWORKFLOW-86 is currently only briefly documented and its intended use case is unclear - at least to me.

The documentation should explain:

• what the publication comment is intended to represent;

• where and how it can be edited;

• that it is stored on the draft's PublicationWorkflowClass object;

• when and how it is copied to the published document's history;

• whether it is intended to be changed for every publication or kept as a persistent document property.

Is this feature intended to provide a per-publication comment? If so, should the field be exposed directly in the Publish UI instead of requiring users to edit the draft's object manually?

(https://forum.xwiki.org/t/documentation-and-possibly-ui-for-publication-comment-edit-feature/18851)