I read this page: http://developer.gimp.org/plug-ins.html
but it only deals with plug-ins for filters.
Is there also a documentation somewhere which describes how to add support for file formats?
Thanks for any help!
the gimp developer mail list would be a good place to ask...But seems temporary in READ ONLY mode for some technical problem
A good alternative, if you have a IRCC client (as chatzilla for FF ) is this
could be needed some time before somebody competent will notice your message but then you get good chances of useful reply
( that may happen even here soon or later, but use the IRC may be quicker )
Registration for the mailing list is working again and I will try my luck there!