2d image editor aka. node based compositor?
Dev: I had this great idea of making this new thing because I haven't seen it before
Everyone Else: Yeah, it looks like this or this or even that. Have you looked at what other people have done and the pain points they solve or cause?
Dev: Nah, this is a totally different idea that nobody's done before.
Everyone Else: Oh, okay, you do you then
*I've been that dev (more than once)
There are also very close cousins like Reason and its rack connections, which could contribute some nodes-101-level concepts to most basic graphical node workflows.
Whatever that is.
Based on replies in the subthread, I understand you mean that this obviously has been done many times before, and the authors didn't know, based on the naming. But let me offer a different perspective.
Gimel Studio looks exactly like what I was searching for. If I found out about it a month ago, I would hold off upgrading Affinity Photo to their newly released version 2, to get more layer-based non-destructive editing features, because Photoshop-style layer-based interface sucks (mostly it's too twiddly and requires too much high-precision mouse operations on a tiny side panel). I actually briefly looked for some 2D node-based image editors, and didn't find any. "Node based compositor" sounds like something from Blender or the film industry, so despite sort of being aware of this, it never occurred to me to search in this space.
Or, in short: for people like me, who are looking for software competing with GIMP, Photoshop, Affinity or Paint.NET, and not Blender or Houdini or whatever else VFX people use, "2D image editor" is obviously meaningful, "compositor" is not.