Nah they use “an open standard” being just markdown files or something, but the apps are still proprietary as far as I’m aware
I really hate how I sometimes, though rarely, see Obsidian talked about as if it were open source just because it uses an open standard
Like Photoshop isn’t open source because it can use PNG kinda thing
The embed on my client only gave me the middle 2 panels for context and honestly still funny