Why is GitHub search so terrible?

A basic, straightforward, exact match search finds nothing: https://github.com/huggingface/transformers/search?q=TFGPT2LMHeadModel

And yet, here it is: https://github.com/huggingface/transformers/blob/4d0ea3d2692ccf2e7f091031fedb1ed8a366ddd2/src/transformers/models/gpt2/modeling_tf_gpt2.py#L814

I saw another thread where they tried to justify not indexing forks, but in this case, this is not a fork; it's one of the most-starred repositories on the entire site.