I think you're asking about the ability to modify XMP within programatically added schemae, right Kelly?
There was nothing new along those lines introduced in 9.1. Works today, as exercised in PProPanel, if you're get/setting a schema that's been activated by the user, in the "Metadata Display..." prefs.
Yes, I'm trying to read and set custom schema XMP metadata.
But also trying to read from Project Metadata.
I have an FCP XML that was created from a Digital Asset Manager (Dalet Galaxy). Within that XML I see:
<mastercomment4>CATEGORIES/LIBRARY/Features/2015/I/Into The Grizzly Maze (2014)</mastercomment4>
These master comments are then created in the project metadata area in PPro. I'm assuming these are custom fields because when I go into the Metadata display, I can delete these properties.
However, these fields are what I'm trying to access. Possible?
You've managed to pick "special case" fields, that only exist if that sequence was imported from an FCP XML.
Any chance you could store your info in an existing, canonical (and more likely to be present) field?