The default XSLT file doesn't include this field. It increases accessibility by making screen readers actually work (otherwise it guesses the system default language and in case it's wrong you're going to listen to garbage), and makes the typesetting prettier since browsers only hyphenate when they know the language.

I think we can make a meta field for this, and set the default to English in the XSLT, since the dates and stuff are all English. It would be even better to fully and properly support internationalization, but this is a good first step.

Somehow I thought I saw that the recursive transclusion rejection feature was implemented. Seems like its not.

It is still possible to accidentally trigger recursive transclusion on the latest branch, using any query in a tree that happens to include the tree itself. This should be patched out.

The code goes like .katex { font-size: 1.2em; }, which will always be ignored by the CSS structure. If this is really needed, it should be modified with !important. But considering that the overriding value is 1.21em this is probably not important (pun unintended). It should probably be removed in case it confuses someone trying to customize on top of the base theme.

A more convenient thing to do is to just use the browser default monospace font. This is already the case with \code{...}, so I guess that's consistent. Monospace fonts usually go out of their way to distinguish O 0 I l 1 etc.