[freshchilled]

There's LogSeq, which is a bit of a different model, but is open source and has all the basic functionality that Obsidian has.

I don't know what kind of formatting you're looking for, but most of the apps I'm familiar with are markdown or just plain text. I use Vimwiki in markdown for my notes, but it can also be exported to HTML, which I don't use often.

[toastal]

Ideally something like reStructuredText or AsciiDoc, both of which have a much larger feature set for taking notes where longer form is needed. I don’t really like the idea of embracing an Obsidian-only fork either.