I did the "report this app" thing with the following message:
I believe the license field for this `geany-gtk` is not correctly set, probably just left at some default. It shoulda be GPL v2, not "Proprietary". I don't know how to contact the contributor who maintains it, so could you please ping them and ask them to fix it?
The full text of Geany's license is here: https://github.com/geany/geany/blob/master/COPYING
The related Geany bug report is here: https://github.com/geany/geany/issues/2497