yt-addiction-control/youtube-addiction-control-extension-firefox.js

// inject CSS

const STYLE_CLASS = "youtube-ac-styling";

Array.from(document.getElementsByClassName(STYLE_CLASS)).forEach((e) => {
    e.remove();
});

let ytacCSS = {
	"sidebar": "#related",
	"comments": "#comments",
	"endscreen": ".videowall-endscreen",
	"invideo": ".ytp-ce-video",
	"notification": "ytd-notification-topbar-button-renderer",
	"other": "#newness-dot, .ytp-spinner"
};

const INVISIBLE = " { display: none !important; }"

let head = document.getElementsByTagName('head')[0];
for (key of Object.keys(ytacCSS)) {
	let e = document.createElement('style');
	e.setAttribute('type', 'text/css');
	e.setAttribute("class", STYLE_CLASS);
	e.setAttribute("id", "ytac" + key);

	if ('textContent' in e) {
		e.textContent = ytacCSS[key] + INVISIBLE;
	} else {
		e.styleSheet.cssText = ytacCSS[key] + INVISIBLE;
	}

	head.appendChild(e);
}

// browser action listener
  
// Listen for messages from the background script.
if (window.ytacListener != null) {
	browser.runtime.onMessage.removeListener(window.ytacListener);
}
window.ytacListener = (message) => {
	console.log("[YTAC] received browser action " + message.command);
  	if (message.command == "comments") {
		console.log("[YTAC] showing comments");
	  	document.getElementById("ytaccomments").remove();
  	} else if (message.command == "sidebar") {
		console.log("[YTAC] showing video sidebar");
		document.getElementById("ytacsidebar").remove();
	} else if (message.command == "invideo") {
		console.log("[YTAC] showing in-video suggestions");
		document.getElementById("ytacinvideo").remove();
	} else if (message.command == "endscreen") {
		console.log("[YTAC] showing endscreen");
		document.getElementById("ytacendscreen").remove();
	} else if (message.command == "notification") {
		console.log("[YTAC] showing notification bell");
		document.getElementById("ytacnotification").remove();
	}
};
browser.runtime.onMessage.addListener(window.ytacListener);
console.log("[YTAC] added action listener");

function modifyThings() {
	let repeating = false;
	// autoplay disabler
	let autoplayButton = document.getElementById("toggle");
	if (autoplayButton == null) {
		console.warn("[YTAC] could not locate autoplay button");
	} else if (autoplayButton.getAttribute("aria-pressed") === "true") {
		autoplayButton.click();
	}

	// description expander
	let showMoreButton = document.getElementsByClassName("more-button");
	if (showMoreButton.length == 0) {
		console.warn("[YTAC] could not locate description expander, trying again in 5s");
		setTimeout(modifyThings, 5000);
	} else {
		showMoreButton[0].click();
	}
}
modifyThings();