No, but there are at least 22 Nexus 7-speed hub part numbers -- so there are 22 potential variations, which is why I used the word "potential" there.
Evidence, no -- but there are 3 variations on the cassette joint, which is a critical part in that shifting system. Maybe they all require the same pull ratio, but that's what I was hoping to confirm. It is possible, isn't it, that MicroShift just built their shifter to work with the most common hubs and called it a day? It's a niche product already, so perhaps "perfect" was decided to be the enemy of "good enough".
No, they aren't going to make one version of 3 or 22 without naming the one that it works with.
And Shimano isn't going to call something "Nexus 7 speed" and then force consumers to decode that.
You have no basis for this notion. It isn't how stuff works.