Well, it’s not in HTML but in database. All the more puzzling that ACF does not pick up on it, as the term for the field is identical.
CCTM a solution for creating custom post types and filters.
I’ll have a look into your remarks, as that involves some more resarch on my end.
Sorry for not getting back to you sooner: not sure what happened there, but apparently the forementioned code is now functional. Thanks.