Ok i cross read most of the toppic, but i can't help to notice a very fatal practical flaw in this very theoretical Discussion:
As long as you can open edit save and playtest the game from MV, how can anyone prove that it was not made with mv?
When kadokawa wants to sue you it's there turn to provide evidence that you didn't use MV and this is not a case where you have to lay open every bit of software installed on your pc.
Well i don't want to incite someone to break the license, just wanna saying that at the end of the day it comes down to this.
So as a rule of thumb i would say "Open, Edit, Save, Play" is fair enought.
If I download your game, and look at the Javascript object descriptions, that tells me that it at some point was a RPG Maker MV project. If you use the MV editor to build the map using MV assets, but then decide to go build the game in Unity still using MV's assets, that is a violation of the licence.
The entire open, edit, save and playtest, means that you have not changed the data structures in a way that the editor would revert upon saving. This is why plugins work at all, because the plugins do not edit the data structures, they merely extend them or offer alternate functionality in a new object that the editor isn't really aware of. If I took the same game where the map had been made in RPG Maker but no assets, then obviously it would not load in RPG Maker MV, and is thus not considered a MV game.
There is some wiggle room in interpretation because you are not required to use node-webkit (nw.js) to play the game, and it's entirely possible to re-implement MV in Unity if one was willing to spend the time on it, but it again comes back to being able to re-open it in MV. The .json files work this way, the core javascript and plugins do not. So if you cloned MV's engine in Unity, you would not be able to use MV's assets unless you still did the majority of the game in MV's editor, thus the editor can still open-edit-save-test. All you would be doing in Unity is replacing the WebGL/Canvas/Pixi.js and plugins overhead with Unity's overhead. That could be faster, it could be slower.
Which is what I mean when people ask about specifics to the license. When people ask, they have a use in mind that they pretty much know already that it violates the spirit of the license, or may violate the license (due to how the assets are packaged,) and they are looking for how to get around it. That goes right back to "are you trying to use MV's assets" or "are you trying to use MV's engine/editor". If you build a game with MV, get to like 95% complete and then get a publisher that says it has to work on the 3DS or the WiiU or something else that doesn't have a native node-webkit build or webview (Nintendo actually does have a web framework, but the WiiU and 3DS are much weaker machines than a desktop) then you would likely be forced to build something MV-compatible for the target platform.
It is less problematic to use MV's editor, or any other editor to build something else than it is to use the assets.
The copyright on the assets belong to KADOKAWA, and thus any use of the RPG Maker assets outside of a RPG Maker game constitutes copyright infringement. This includes using the assets as examples in webpage tutorials or video tutorials, regardless if they are RPG Maker tutorials or not (eg people use them in tutorials for Unity.) This is why artists get super-upset when someone posts their image to imgur instead of linking to their webpage/tumblr/deviantart. People just save stuff they find on the internet to their hard drive and share it through unofficial means, losing copyright information in the process, and then people mistakenly believe the content to be public domain. I have seen first-hand people using sprites that look exactly the same as RPG Maker's and Square-enix's assets, and there are assets IN RPG Maker that could readily be mistaken for Square-enix assets. One of the huge differences between the USA and Japan is that the Japanese tend to care less about copyright infringement (see Comiket) so long as the artwork is drawn new in fan productions (doujin) and not stolen from another artist. In the USA there is this bizarre obsession by fans stealing other fans fanart and putting it on t-shirts, which is even worse. So what I'm getting at here is that if you use KADOKAWA's RPG Maker assets outside of RPG Maker, you would absolutely deserve any legal repercussions for doing so. If you start making T-shirts of the characters in your game that were generated by the RPG Maker character Generator, you can't do that, because that is not what the license is for.
If you use the editor to build a non-MV game, using non-MV assets, that's pretty much a non-issue. You may want to go "made with RPG Maker MV" but if you are building your own engine and only converting the output from MV to this other engine then from a legal perspective you are not using any assets or code from RPG Maker MV, and thus you can't open it back in MV and it is not a MV game. Out of politeness you'd want to credit who made your tools, but you don't need to provide a way for every-joe to edit your game. Now on the other hand, if you decide to make your game mod-able, and modding requires MV, then you can not give users RPG Maker MV to make mods.
There is always going to be some kind of edge case that no license can completely black-or-white approve. If in doubt, contact the developers (not the forum) and seek legal advice and get a firm yes or no. Do not assume that no response means tentative approval.