Note that IIRC the reason Geany doesn't actually install the GIR file is that there (was) not enough testing regarding its quality. And also that the only *direct* consumer would be Vala, as other languages would still require a loader ([Peasy](https://github.com/kugel-/peasy) being the obvious candidate).
I don't know how many plugins exist using Peasy, or basically how tested is the GIR file; but if it's tested enough and has appeal, we could install it. We probably would *not* commit to any stability there (yet), but that might be acceptable to most (and I don't mean we'd willfully break it, but that we probably wouldn't carefully *not* break it, at least not until it shows some actual users).