There has been this feature request on Meta.SE since 2012: Add syntax highlighting for the MATLAB language
In May 2016 it was marked as [status-completed] and the following answer was posted by an SE admin:
Matlab syntax support is rolling in.
This is basic syntax support without keywords, as these add a lot to the size of the highlighter and do not gzip well at all.
Still - comments should be comments and basic highlighting should work as expected.
This is great. I verified some time ago that it also works on our site: Matlab code gets highlighted correctly if I preface it with
<!-- language: lang-matlab -->.
However, it does not work automatically when a thread carries a matlab tag. I noticed it now in this question. It seems that it does work on StackOverflow though, or at least that's how I interpret the following comment:
\o/ It's so working! All my posts suddenly became gorgeous! – Adriaan May 20 at 15:59
So it might be that the automatic highlighting for matlab has not been rolled in specifically on CrossValidated. Hence I post it as a bug.