Actually, what’s fascinating in this manuscript is the unfinished decoration allowing an insight into how it was done in the 15th century. On folio 23v only the gilding has been done, but later everything’s only sketched in. The feather-work pattern seems to have been such an obvious thing it wasn’t even sketched in, only the larger details (e.g. flowers) it connected.
See also: Fully bordered page (folio 1r)