The documentation for genealogytree says in section 7.1 (Database Concept):
The content producer could be a human person directly, but more presumably a machine like a genealogy program. The node content is written as a comma separated key-value list. This list is processed and its content formatted by a database processor.
But are there any examples of code for genealogy programs to output in a format suitable for genealogytree? I have used genealogytree several times and have really liked the output, but only with handwritten input. Now when I want to use data from a GEDCOM file (the most usual format for exchanging genealogical data) I thought that I remembered some (experimental?) code for importing data from a GEDCOM file that came with genealogytree, but it seems like I remember wrong (or it is no longer there).