So I’m still working with 6G60, but Mike, I don’t see how that changelog would mean that Conditional Backdrops is obsolete. It doesn’t mean you can move backdrops to any arbitrary description of rooms, just “everywhere” and “nowhere.” (You can move backdrops to “everywhere” in 6G60 already, and as the log says they’re the only things that can be everywhere.)
Ron, as you said Original Parser is obsolete, but in case you want to rework it: did you ever see this bug with getting run-time errors when inserting a disambiguation response into the original command?