Hi Loic,
I recently noticed that the history of software is severely underrepresented on Wikidata and there is very little interlinking going on at all, while many items are missing P31. I do think it would be useful to create a Wikidata:<Software project> page to list the various types of software (OS, languages, development environments) and model how to use properties to flesh out such items. I suspect there are several properties that need to be created, such as "Principal developer" or something like that.
I agree however that for a low-threshold Wikidata meetup, the most important thing is to share basic gadgets and knowledge, because there is so much still to be done on outreach in all languages. I noticed for example that Listeria was blocked on Portuguese Wikipedia due to objections in the labelling showing up in list headers. This shows how the basic interface is still such a mystery to so many communities, probably because the basic interface is still so incomplete in those languages.
Jane