Links in ToC of TGR don't work in many cases

In many projects in TGR, links don't work properly. For example: https://textgridrep.org/browse/46zhp.0

In the Digital Library, the links work: https://textgridrep.org/browse/kq6v.0#tg7.2.1

In many projects we've published in recent years, such as CoNSSA, ELTeC, textbox... the links don't work.

Apparently, the portal needs the head element to have an xml:id attribute in order to use it for the link. Most projects don't have these ids and won't include them in their TEI files.