Showing/Changing Bookmark Folder in #detailsDeck of places.xul

Users often express hope that the Library window bookmark search results will gain a “current folder” column or “go to folder” context menu item. Since legacy extensions were deprecated, this has not been possible.

Imagine my surprise when I discovered that these elements from the Add/Edit Bookmarks dialog are present (but hidden) in the #detailsDeck of the Library window:

<vbox id="editBMPanel_folderRow" collapsed="true">
<vbox id="editBMPanel_folderTreeRow" collapsed="true">

If I override the visibility: collapsed state, they are not populated with the current folder of the selected bookmark (in a search results list, for example).

It seems the plumbing is in place for a nice feature, but the script to populate those fields is absent.

Does it seem feasible for someone to figure out what code populates the current folder into the Add/Edit bookmark dialog and get that into the Library, adding it to whatever code fills the other fields in that panel?