I wonder if GPT et al. would help with this kind of thing, or if it's too esoteric.
If you thought BT was huge, the cellular mobile specs (ETSI GSM etc.) are more than an order of magnitude bigger and more complex.
Its an 80 page document.
So, I guess this is a document that has two columns, the abbreviation and a reference to the document that defines it, without mentioning the long form?