[Allan_Smithee]

The guy who wrote Github is responsible for some of the worst coding atrocities in a major piece of F/OSS. (Evidence: the Linguist debacle.)

JS for Cats is, in comparison to Linguist, a work of towering intellect.

[rurounijones]

More info? I have never heard of anything bad about Linguist (And I don't know that much about it.).

Googling didnt bring up anything obvious,

[anaphor]

Parent might be referring to the fact that it can easily give false positives, but I'm not sure.

[bm1362]

I think it's the project that does syntax highlighting for the code browser in Github?

[rurounijones]

It is the software the identifies % of language used in a repository and highlighting etc. https://github.com/github/linguist

I just haven't heard anything bad about it so am curious why OP calls it a "debacle"