jeb5

const channels = [...document.querySelectorAll("#main-link.channel-link")].map(e => {
	const [, a, b] = e.href.match("/((?:user)|(?:channel))/(.*)$");
	const feed = "https://www.youtube.com/feeds/videos.xml?" + (a === "user" ? "user=" : "channel_id=") + b;
	const channelName = e.querySelector("yt-formatted-string.ytd-channel-name").innerText;
	return [feed, channelName];
});
if (channels.length == 0) {
	alert("Couldn't find any subscriptions");
} else {
	console.log(channels.map(([feed, _]) => feed).join("\n"));