Can pyRevit add a revision delta to the revision schedule?
Yes you can do that with the Revit API. There is a “Set Revision on Sheets” tool under Revision that can set any of the revisions on the sheet without a revision cloud
Thanks for your reply. this works fine but does not add the delta symbol in front of the revision description. Is this something pyRevit can do?
No. The revisions show up in a schedule in the title block and as far as I know there is not a non-hacky way to add a triangle in front of every revision. We usually draw a triangle at the top of the revision number column.