In the Feldheim Tikkun Korim, there is some commentary by Sha'arei Mesorah, Ma'aneh Lashon, and Shita Mekubetzet.
From what I can deduce, they are specifically about technicalities of leyning, a mesorah beyond the trope. Something like "Say these words [high|loudly]" or "Say these words closer together."
I would love to delve into that when preparing leyning, but it's so technical (and often so abbreviated) that it's beyond me. Where can I find a good resource to understand the technical words and abbreviations used when talking about layning? I'd ideally like one for English readers, but Hebrew is fine.