### Context NBSphinx supports prepending a jinja2 rendered pro- and epilogue to the output. See https://nbsphinx.readthedocs.io/en/0.3.0/prolog-and-epilog.html ### Proposal I wonder if it'd be easily possible to implement this as well in MyST-NB. What would be a good starting point inside the code base? ### Tasks and updates _No response_