I was wondering is there any reason for hardcoding the GDS datatype (texttype) to 0 for annotation layers like pin_text etc. ? Referring to line 333 of gds_base.py from Nazca-0.5
Yes, only for datatype = 0 annotations seem to show up in layout viewers. (This possibly depends on the specific viewer as well.) And as you mentioned already, annotations formally do not have a datatype but a texttype.