Update: Added Support for Youtu.be

DetachableYoutube.plugin.js

//META{"name":"detTube"}*//
function onYouTubeIframeAPIReady(){
	console.log("Youtube API Ready");
}
function detTube() {
	//construction
	var self = this;
	var setupComplete = false;
	var utubeURL = "https://www.youtube.com/";
	var utubeApi = "https://www.youtube.com/iframe_api";
	var currentVideo = "";
	var supportedUrls = new RegExp('(^https:\/\/www.youtube.com\/)|(^https:\/\/youtu.be\/)')
	this.log = function(){
		// var args = Array.prototype.slice.call(arguments);
		// args.unshift("%c["+self.getName()+"]", 'font-weight: bold;color: green;');
		// console.log.apply(console,args);
	}
	this.init = function(){
		self.css = "<style class='detTubePlugin'>"+
		".detTubeWindow{"+
			"float:right; z-index:2; background-color: #2e3136; position:absolute; bottom:0; right:0; color:#FFF; padding: 4px; border-radius: 4px;"+
		'}'+
		".detTubeInner{position:relative;}"+
		'.buttonClose{'+
			'background: transparent url(https://discordapp.com/assets/14f734d6803726c94b970c3ed80c0864.svg); background-size: cover; transition: opacity .1s easeout; opacity: .5; width:12px; height: 12px; padding: 0'+
		'}'+
		'.buttonClose:hover{opacity:1;}'+
		'.detTubeWrapper{'+
			'height:0; width:auto;position:relative;'+
		'}'+		
		'.detTubeWrapper .btn{cursor: pointer;}'+
		'.detTubeWindow>*+*{'+
			'margin-left:5px;'+ 
		'}'+
		'.detTubeInner>.buttonClose{'+
			'position:absolute; right:0; top:0;'+
		'}'+
		'.detTubeInner>.buttonClose:last-child{display:none;}'+
		'.detTubeWindow .embed{border-left:none; padding:0; margin:0;}'+
		'.detTubeWindow div:not([class]):nth-child(1), .detTubeWindow div:not([class]):nth-child(2){display: inline-block;}'+
		'.detTubeWindow .embed-provider{color: #FFF;display: inline-block;background-color: #E55;border: solid #E55;border-radius: 4px;}'+
		'.detTubeWindow .embed-author{font-size: 12px;border: solid #EEE;display: inline-block;background-color: #EEE;border-radius: 4px;}'+
		'.embed .embed-video-actions .embed-video-play.detTubeButton{background-image:url(https://i.imgur.com/6pQAhEZ.png);}'+
		'.embed .embed-video-actions.detTubeFloatingWrapper{position: absolute; top:0; left:100%; bottom:initial; right:initial;opacity:.6;}'+
		'.embed .embed-video-actions.detTubeFloatingWrapper .embed-video-actions-inner{padding:8px;}'+
		'.embed .embed-video-actions.detTubeFloatingWrapper:hover{opacity:1;}'+
		'.detTubeFloatingWrapper .detTubeButton{background:none;background-image:url(https://i.imgur.com/6pQAhEZ.png); width:19px; height:19px;background-size:19px 19px;}'+
		'.detTubeWindow .detTubeFloatingWrapper {display:none;}'+
		'.detTube-dragging iframe{pointer-events:none;}'+
		'.detTube-disableSelection{user-select:none;-moz-user-select: none;-webkit-user-select: none;}'+
		'</style>';
		self.markup = "<div class='detTubeWrapper'><div class='detTubeWindow'><div class='detTubeInner'><button id='detTubeClose' class='btn buttonClose' type='button'></button></div></div></div>"
		self.button = "<button class='detTubeButton embed-video-play' type='button' style='background-image:url(https://i.imgur.com/6pQAhEZ.png);'></button>"
	};
	self.process = function(){
		if(!setupComplete){self.setup()}
		$(".embed-video-popout:not([data-dettube-scanned])")
		.each(function(i,el){
			el.setAttribute("data-dettube-scanned","")
		})
		.filter((i, el) => self.log(el.href,supportedUrls,el.href.match(supportedUrls)) || !!el.href.match(supportedUrls))
		.each(self.log)
		.before(self.button)
		.closest(".embed")
		.each(function(i,el){
			self.observer.observe(el,{childList: true})
		})		
	};
	self.deactivateAutoplay = function(){
		frame = $(".detTube_detached iframe")
		if (frame.length){
			frame.attr("src",frame.attr("src").replace("&autoplay=1&auto_play=1","&autoplay=0&auto_play=0"))
		}
	}
	self.setStartTime = function(frame,time){
		var src = frame.src.replace(/&start=(\d+)/,"");
		frame.src= src+"&start="+time;
	}
	self.enableJSControl = function(iframe){
		if (iframe.src.indexOf("enablejsapi")==-1){
			iframe.src += "&enablejsapi=1";
		}
	}
	
	self.detachVideo= function(vid){
		currentVideo = vid.find(".embed-title").attr("href")
		//if .embed contains an iframe a vid has been expanded
		var subframe = vid.find("iframe")

		if (subframe.length){
			vid.data("move",true);
			var p = new YT.Player(subframe[0],{
				events:{
					onReady:function(e){
						self.log("READY!")
						if(vid.data("move")){
							vid.data("move",false)
							var time = Math.floor(e.target.getCurrentTime());
							self.log("Time is "+time)
							//e.target.destroy();
							self.setStartTime(subframe[0],time);
							vid.before("<div class='detTube_placeholder'></div>").detach().appendTo(".detTubeInner").addClass("detTube_detached");
						}
						
					}
				}
			});
			subframe[0].src+=""
		}else{
			//no iframe
			vid.before("<div class='detTube_placeholder'></div>").detach().appendTo(".detTubeInner").addClass("detTube_detached");
		}
		
	};
	self.reattachVideo = function(){
		var old = $(".detTube_placeholder");
		self.log("placeholders: "+old.length)
		self.log("detached: "+$(".detTube_detached").length)
		if(old.length){
			self.deactivateAutoplay();
			old.before($(".detTube_detached").removeClass("detTube_detached").detach()).remove();
		}else{
			$(".detTube_detached").remove();
		}
	}
	self.moveWindowListener = function(e){
		self.log("mousemove")
		var elem = $('.detTubeWindow')[0];
		var pos = elem.parentElement.getBoundingClientRect();
		if(elem.style.right == ''){
			elem.style.right = '0px';
			elem.style.bottom = '0px';
		}
		elem.style.right = Math.max(parseInt(elem.style.right)-e.movementX,pos.right-window.innerWidth)+'px';
		elem.style.bottom = Math.max(parseInt(elem.style.bottom)-e.movementY,pos.bottom-window.innerHeight)+'px';
	};    

	self.setup = function(){
		if (!$(".content > .flex-spacer.flex-vertical").length) return;
		self.log("setup")
		$("head").append(self.css);
		self.window = $(self.markup);
		
		$(".content > .flex-spacer.flex-vertical").append(self.window);
		self.window.find("#detTubeClose").click(self.reattachVideo);
		setupComplete = true;
		var that = $(".detTubeWrapper").on("mousedown.detTube",function(){
			self.log("mousedown")
			that.addClass("detTube-dragging");
			$(".app").addClass(".detTube-disableSelection");
			window.addEventListener('mousemove', self.moveWindowListener, false);
		})
		$(window).on("mouseup.detTube",function(){
			$(".detTubeWrapper").removeClass("detTube-dragging")
			self.log("mouseup")
			$(".app").removeClass(".detTube-disableSelection");
			window.removeEventListener('mousemove', self.moveWindowListener);
		}) 
	}
	self.onSwitch = self.process;
	self.onMessage = self.process;
	self.stop = function(){
		
	};
	self.start = function(){
		var tubeAPI = document.createElement('script');
		tubeAPI.src = utubeApi;
		document.body.appendChild(tubeAPI);
		$(".content").append(self.window)
		$(".app").on("click",".detTubeButton",function(){
						self.reattachVideo();
						self.detachVideo($(this).closest(".embed"))
		})
		/*
		========================================
		|Mutation Observer for IFrame Insertion|
		========================================
		*/
		self.observer = new MutationObserver(function(mutations) {
			var embed = mutations.target;
		  mutations.forEach(function(mutation) {
			self.log(mutation);
			for(i=0;i<mutation.addedNodes.length;i++){
				var node = mutation.addedNodes[i];
				//check if it contains a youtube iframe
				if (node.firstChild.nodeName == "IFRAME" && node.firstChild.src.match(supportedUrls)){
					self.enableJSControl(node.firstChild)
					$("<button class='detTubeButton'></button>")
					.appendTo(node)
					.wrap("<div class='embed-video-actions detTubeFloatingWrapper'> <div class='embed-video-actions-inner'></div></div>")
				}
			}
		});
		//Mutation Observer End/////////////////
		
		self.process();
});
	};
	self.getName = function(){return "detTube"};
	self.getDescription = function(){return "Detatch youtube to make it moveable"};
	self.getVersion = function(){return "1.2"};
	self.getAuthor = function(){return "Megamit/Mitchell"};
	self.load = function(){};
	self.unload = function(){};
	this.init();
}

Im sorry, but how do I use this exactly?

Yeah, how do I use this?

There is an icon that should pop up on the lower right side of your video. The video will pop up on the right corner of your screen and you should be able to drag it around afterwards. @Denny966

not working anymore.... even after correcting the order of the flex... classes (they're the other way around now....)

not working anymore.