Pandoc: What survives a conversion?

I have been working on a new (post-markdown) markup language Carve. And I wanted to know how it performs for input and output. Especially compared to Markdown and Djot, which mainly inspired me here. And it happens that Pandoc released 3.10.2 recently. Everyone who converts documents knows the process loses things. Tables are fine in most formats. LaTeX keeps everything. Word is a black hole. Some of that is true. Some is backwards. You cannot tell by looking, because the failure is quiet – the file still opens, the paragraphs are all there, and the one attribute that carried your meaning is gone. So: 66 features, every format pandoc writes, one grid. Why the obvious experiment fails Write a document, convert it, read it back, diff against the original. That is the test everyone reaches for and it does not work. Writers restyle. Yours rewraps lines, renumbers lists, relocates link definitions, swaps * for _. Diff against the input and the noise buries the signal. Loosen the diff until…