Is View Rendered Source safe?

function launchVRS() {
	chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
			
		//get current tab position so we can open new tab next to it (at index + 1)
		var tabPosition = tabs[0].index;
		var tabID = tabs[0].id;
		
		chrome.tabs.sendMessage(tabs[0].id, {"message": "Gimme the rendered DOM"}, function(response) {

			if(response) {

					var renderedObjURL = response.payload;
					var renderedStorageKey = "VRS|" + tabs[0].id;
					var doctypeKey = "VRSDOCTYPE|" + tabs[0].id;
					var UAKey = "VRSUA|" + tabs[0].id;
					
					//add reference in storage to blobURL of rendered page
					chrome.storage.local.set({ [renderedStorageKey]: renderedObjURL });
					chrome.storage.local.set({ [doctypeKey]: response.doctype });
					chrome.storage.local.set({ [UAKey]: response.userAgent });

					chrome.tabs.create({ url: 'viewrenderedsource.html?tabID=' + tabID, index: tabPosition + 1});
			} else {
				//no response from content.js -- not much we can do...
			}

		});
	});
}


//user clicked Browser Action button or used keyboard shortcut
chrome.action.onClicked.addListener(function (info) {
	launchVRS();
});

// create context menu (right click menu)
chrome.contextMenus.create({
	id: "vrs_context_menu",
	title: "View Rendered Source (Alt+U)", 
	contexts:["page"]
});

// Listen for the context menu item click
chrome.contextMenus.onClicked.addListener(function(info, tab) {
	if (info.menuItemId === "vrs_context_menu") {
		launchVRS(); 
	}
});

// Listen for the keyboard shortcut
chrome.commands.onCommand.addListener(function(command) {
	if (command === "_execute_action") {
		launchVRS();
	}
});

chrome.tabs.get(parseInt(tabID), function (tab) {

		//for some reason there's no way to query if a tab still exists so have to look for error
		if (chrome.runtime.lastError) {
			alert('Error: Original tab has been closed. Reload original tab and launch extension again.');
			return
		}

		//get URL of tab that opened us so we can fetch raw source
		rawURL = tab.url;
		d.title = 'View Rendered Source: ' + rawURL.substring(0, 150);
		currentURL.innerHTML = 'URL: ' + rawURL;
		currentURLHref.href = rawURL;

		var doctypeKey = "VRSDOCTYPE|" + tabID;
		var userAgentKey = "VRSUA|" + tabID;
		var renderedDOMKey = "VRS|" + tabID;

		chrome.storage.local.get(doctypeKey, function(result) {
			doctype = result[doctypeKey];
		});

		chrome.storage.local.get(userAgentKey, function(result) {
			userAgent = result[userAgentKey];

			//Detect if mobile
			if(/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino/i.test(userAgent)||/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(userAgent.substr(0,4))) {
				
				// fetchTypeRendered.innerHTML = 'Chrome, Mobile <div class="tooltip" style="width:15px; height:15px; font-size:14px; font-weight:800">i <span class="tooltiptext">To render as a mobile device, <a href="https://developers.google.com/web/tools/chrome-devtools/device-mode/emulate-mobile-viewports" target="_blank">change the device in Chrome DevTools</a> and re-launch extension</span></div>';
				// fetchAsMobile.checked = true;
			} else {
				// fetchTypeRendered.innerHTML = 'Chrome, Desktop <div class="tooltip" style="width:15px; height:15px; font-size:14px; font-weight:800">i <span class="tooltiptext">To render as a mobile device, <a href="https://developers.google.com/web/tools/chrome-devtools/device-mode/emulate-mobile-viewports" target="_blank">change the device in Chrome DevTools</a> and re-launch extension</span></div>';
			}
			
		});


		//now get Blob URL of rendered source 
		chrome.storage.local.get(renderedDOMKey, function(result) {
			var renderedBlobURL = result[renderedDOMKey];
			fetchSource(renderedBlobURL, 'rendered');
			fetchSource(rawURL, 'raw');
		});
	});

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