[...] when necessary [...]

Any estimations of when communities should converge their efforts? Or rather, when is it not too early for communities to prepare their projects (night mode stability)?

Hey @Lofhi, yes, we're almost ready, and we will reach out to you (the frwiki community) soon, maybe even this week, with more specific information and questions.

Now I can say that we'd like to start with mobile web, and deploy on desktop as a beta feature next. You can check the planned sequence of deployments here (skins + desktop/mobile + logged-in/out, no dates).

Would Francophone Wikipedians be interested in getting this early, as a pilot wiki? what do you think?

I believe the entire community would be willing to participate as pilots for the new night mode, given their constructive contributions when they participated as one of the few major wikis to test the new discussion tools early on.

But the problem is, what do the technical contributors think? I will try to gather their feedback.

In T356344#9601739, @Lofhi wrote:

But the problem is, what do the technical contributors think? I will try to gather their feedback.

I have a handful of contributors who are interested or could be. As you can imagine, technical profiles are not the most numerous. I think that might be enough, and in any case, we'll have to work on it sooner or later.