Get a list of users who have sent a chat message in a Google Meet

copy-meet-chat.js

// To run (in Chrome):
// MUST HAVE GOOGLE MEET CHAT VISIBLE!
// Press F12 to open Developer Tools
// Click the "Console" tab
// Copy and paste the code below

function copyToClipboard(str) {
	var tempInput = document.createElement("input");
	tempInput.style = "position: absolute; left: -1000px; top: -1000px";
	tempInput.value = str;
	document.body.appendChild(tempInput);
	tempInput.select();
	document.execCommand("copy");
	document.body.removeChild(tempInput);
}

//find the chat element
var list = document.querySelectorAll('[aria-live="polite"]');
//find the messages
var messages = list[0].querySelectorAll('div');
var names = [];
messages.forEach(msg => {
	//get names from elements
	let name = (/(^.*?[a-zA-z])\d/).exec(msg.textContent);
	//if it's a name you haven't had before, add it to the list
	if (name !== null && name[1] !== null && !names.includes(name[1])) names.push(name[1]);
});
names.forEach((name, i) => {
	//remove names that aren't names; also you
	if (!(/^(\b[A-Z][\w\']*\s*)+$/).test(name) || name === "You") names.splice(i, 1);
});
let namesAsString = '';
//make it a list instead of an array
names.forEach((n, i) => namesAsString = i === 0 ? n : namesAsString + ', ' + n);
//copy list to your clipboard
copyToClipboard(namesAsString);
//now you can paste it where you want

If you are so bold, you can create a bookmark and paste the following as the page (name can be whatever you want):

javascript:(function(){function copyToClipboard(e){var t=document.createElement("input");t.style="position: absolute; left: -1000px; top: -1000px",t.value=e,document.body.appendChild(t),t.select(),document.execCommand("copy"),document.body.removeChild(t)}var list=document.querySelectorAll('[aria-live="polite"]'),messages=list[0].querySelectorAll("div"),names=[];messages.forEach(e=>{let t=/(^.*?[a-zA-z])\d/.exec(e.textContent);null===t||null===t[1]||names.includes(t[1])||names.push(t[1])}),names.forEach((e,t)=>{/^(\b[A-Z][\w\']*\s*)+$/.test(e)&&"You"!==e||names.splice(t,1)});let namesAsString="";names.forEach((e,t)=>namesAsString=0===t?e:namesAsString+", "+e),copyToClipboard(namesAsString);})();

Then, if you click the bookmark while a Google Meet chat is open, it'll automatically copy the names to your clipboard.