A tool may parse the json canvas file and extract information such as "there are three ideas linked to this book". Another tool may output an SVG.
I agree with you that posting Obsidian's spec to start the conversation would have been welcome, but this is not what they did.
You shouldn't need to ask permission or consult anyone to do this. That's a silly bar, 'egregious' even. When markdown was created, Gruber wasn't asking all his friends making text editors whether they'd support it. He just released it, and others chose to adopt it on its merits.
I don't meant this to sound harsh, but just to call it as I see it - your comment is basically creating a 'damned if you do, damned if you don't' scenario and an example of why people building things shouldn't worry much about comments in forums.
Many of the best projects that become defacto standards start as a solution to a very specific and real problem that had no public input.
If JSON canvas isn’t a good solution for broad adoption/interoperability, it won’t become one. The world is not harmed by its release, and at worst, it’s now far easier for people building software to understand and make tools that can interact with Obsidian. At best, it becomes a solid foundation and option for tools going forward.
Obsidian didn’t have to do anything here. I’m glad they did.
SVG really stretches the “human readable” thing to its limit, and I personally would not adopt an SVG-like format for anything that isn’t SVG.
(Given that this is coming from obsidian, I kind of expected something actually markdown-like - which would certainly be a challenge, but not an impossible one.)
Granted, this notation is a little higher level than SVG, so the model mismatch might be a bigger problem anyway?