Seems the docs doesn’t contain the answer. Looks like that part was moved elsewhere with latest transaction.
The aim is to access encodeFunctionSignature() for knowing to which function name the selector
82661dc4 belongs to in theᴅᴀᴏ contract.
You can lookup 82661dc4 via the 4byte.directory:
See here: https://www.4byte.directory/signatures/?bytes4_signature=0x82661dc4
web3.eth.abi is part of web3.js 1.2.x, while Metamask uses web3.js 0.2.x
See this link on how to use web3.js 1.2.1 with metamask:
problem connecting web3 v 1.2.1 with metamask : 'currentProvider' of undefined