See #2781 (comment). Tables 37, 38, and 39 define abbreviations to be used with a grammar notation that allows referring to codepoints by these abbreviations. See §5.1.5.1 Terminal Symbols:

In the lexical and RegExp grammars, Unicode code points without a conventional printed representation are instead shown in the form "<ABBREV>" where "ABBREV" is a mnemonic for the code point. These forms are defined in Unicode Format-Control Characters and White Space.

I'd prefer to skip defining our own abbreviations used for indirection and just list the code points directly in the grammar using either the same notation or something similar.