Answering my own question...
I ended up circumventing the problem - that is, the exporter - by
> What I would like to do now is to automatically run some commands
> after I have exported an org file as html.
creating a code block in which I first run org-html-export-to-html and
then do my git stuff. I no longer use the exporter, I just evaluate the
block.
Lesson learned.
Jarmo