Is TiddlyWiki written in itself?

Just to be sure. TW needs a plugin to deal with Markdown syntax.

The TW markdown plugin is a bit special too. If it sees syntax, that it does not know it hands the text over to the TW parser. … That makes it possible to use TW wikitext in combination with markdown. … Especially, it allows us to use the TW KaTex plugin to render math formulas.

… But I thin Jupyter has its own math plugin or something similar.

Sorry, I do not see how these may be related… Can you somehow add a parameter so that a transclusion is editable?

Maybe using this syntax from this post?
{{HelloThere||EditLink}

Thanks, I already knew about the plugin but I didn’t knew it handles syntax when TW doesn’t know what to do

The parser is identified with the type-field. … The default type for tiddlers is text/vnd.tiddlywiki even if no type is set …

Markdown tiddlers have the type text/Markdown or text/x-markdown. So TW knows what to do

The TW type-field is the official mime-type