The REX.Content parameter is built-in and can't be modified. I'd wager the 00_isq_hoogte_min_2 is part of the rebar system in Revit and also can't be modified, but I don't know enough about the rebar (or the translations to what I'm assuming is Dutch (?))
If you need a new GUID, I'd go here: https://www.guidgenerator.com/
If you need a new GUID, I'd go here: https://www.guidgenerator.com/
Comment