Looking at the generated source code, the SVG is getting adding as an HTML "object", rather than as an "img", which I'm guessing means that the image processing logic in https://github.com/python/pythondotorg/blob/master/peps/converters.py#L231 isn't triggering properly.

If I can work out how to do it, I expect the simplest fix will be to get the HTML to render with an img tag instead, but failing that, then I may need to work out how to get python.org's PEP rendering to handle HTML object tags in addition to images.

(@berkerpeksag Any suggestions on how tricky the last option might be?)

It looks like this is coming from an old docutils rendering setting that aims to make SVGs compatible with IE6: https://sourceforge.net/p/docutils/code/HEAD/tree/trunk/docutils/docutils/writers/html4css1/__init__.py

#702 works around the immediate problem with PEP 1 by going back to a fixed size PNG (400x200).

Beyond that, I'm going to close this issue in favour of #2, since a big part of the problem here is that we're using docutils directly, with a dedicated PEP specific HTML writer that's generating HTML 4.1 with assorted legacy IE6 backwards compatibility cruft.