„Mainz“ is not listed in the TGN API's responses to use with the Datasheet-Editor

...seems to be based on missing georefs not returned with our TGN API. See:

http://www.getty.edu/vow/TGNFullDisplay?find=Mainz&place=&nation=&prev_page=1&english=Y&subjectid=7004449 has georefs included,

https://ref.de.dariah.eu/tgn/v1/exact-match?q=Mainz&georef=true has not.