#What it is
A complete working ARKit scene, driven by Unity, running inside a Flutter app on top of Flutter Unity Widget.
It exists because the same integration question kept arriving in the widget's issue tracker: how do you get ARKit's camera and tracking working when Unity is hosted inside a platform view rather than owning the whole screen? Answering that in a comment thread never worked. One complete repository people could clone and run did.
It picked up 235 stars of its own, which suggests the question was considerably more common than the issue tracker showed. Writing one good example and linking it turned out to be the highest-leverage support move available.