Currently, if the highlightjs-lang extension is enabled, the language of the fenced code block will be added as a HTML class to the code element. E.g. for Python code blocks, a python class will be added to the block.

However, a more common and interoperable technique is to prepend the language name with language-, e.g. language-python. This is mentioned in the WHATWG HTML standard and is expected by a variety of other tools and clients (an example being the Element Matrix client). I personally encountered this issue while trying to use urlwatch (which depends on python-markdown2) to send Markdown reports to Matrix.

Would you consider changing this or adding a configuration option for it?