Do you mean BIP-0329?
Yes, I that's the standard I was talking about.
You can export them. Wallet menu > labels > export
Yes, that's right. I now remember that I have seen that option in Electrum before but totally forgot about it. I guess it's fair to assume that the exported file can only be imported back to Electrum and not any other wallets, right? which is another reason why Craig Raw created BIP0329 in an attempt to standardize it.