[Koha-devel] Is MARC support in Koha only partial?

Hi list, I just saw the following web page: http://www.loc.gov/marc/bibliographic/ecbdlist.html ... and I am thinking to myself that perhaps Koha doesn't support all the fields, subfields and indicators that are present in MARC21. I base my assumption on the fact that marc_tag_structure and marc_subfield_structure tables do not have them all there. Would it be right to assume that if those tables had all the fields with indicators and subfields that MARC21 specification includes then we would be able to create an input form to properly catalog new bibliographic records for later exporting them into iso-2709 file? Useful for sharing bibliographic records with other libraries. Benedict