javascript:
(function() {

	mw.loader.using(['mediawiki.api']).done(function() {

		var backlog = mw.util.addPortletLink(
			'p-personal',
			'#',
			'adminbacklog',
			'pt-backlog',
			'adminbacklog',
			'',
			'#pt-userpage'
		);
		var path = mw.config.get('wgArticlePath');
		backlog.innerHTML =
			'<a id="adminbacklog-csd" href="' + path.replace('$1', 'Category:快速删除候选') + '">CSD 未取得</a> ' +
			'<a id="adminbacklog-ep" href="' + path.replace('$1', 'Category:維基百科編輯被保護頁面請求') + '">EP 未取得</a> ' +
			'<a id="adminbacklog-ub" href="' + path.replace('$1', 'Category:封禁及禁制申诉') + '">UB 未取得</a> ';

		var api = new mw.Api();
		function getCSD() {
			api.get({
				action: "query",
				format: "json",
				prop: "categoryinfo",
				titles: "Category:快速删除候选"
			}).done(function(data) {
				$.each(data.query.pages, function(i, item) {
					document.all["adminbacklog-csd"].innerHTML = 'CSD ' + item.categoryinfo.size;
				});
			});
		}
		function getEP() {
			api.get({
				action: "query",
				format: "json",
				prop: "categoryinfo",
				titles: "Category:維基百科編輯被保護頁面請求"
			}).done(function(data) {
				$.each(data.query.pages, function(i, item) {
					document.all["adminbacklog-ep"].innerHTML = 'EP ' + item.categoryinfo.pages;
				});
			});
		}
		function getUB() {
			api.get({
				action: "query",
				format: "json",
				prop: "categoryinfo",
				titles: "Category:封禁及禁制申诉"
			}).done(function(data) {
				$.each(data.query.pages, function(i, item) {
					document.all["adminbacklog-ub"].innerHTML = 'UB ' + item.categoryinfo.pages;
				});
			});
		}
		if (typeof window.AdminBacklogCSD === "number") {
			setInterval(getCSD, window.AdminBacklogCSD);
		}
		if (typeof window.AdminBacklogEP === "number") {
			setInterval(getEP, window.AdminBacklogEP);
		}
		if (typeof window.AdminBacklogUB === "number") {
			setInterval(getUB, window.AdminBacklogUB);
		}
		getCSD();
		getEP();
		getUB();

	});

})();

javascript:
(function() {

	mw.loader.using(['mediawiki.api']).done(function() {

		var backlog = mw.util.addPortletLink(
			'p-personal',
			'#',
			'adminbacklog',
			'pt-backlog',
			'adminbacklog',
			'',
			'#pt-userpage'
		);
		if (!backlog) {
			return;
		}
		var path = mw.config.get('wgArticlePath');
		backlog.innerHTML =
			'<a id="adminbacklog-csd" href="' + path.replace('$1', 'Category:快速删除候选') + '">CSD 未取得</a> ' +
			'<a id="adminbacklog-ep" href="' + path.replace('$1', 'Category:維基百科編輯被保護頁面請求') + '">EP 未取得</a> ' +
			'<a id="adminbacklog-ub" href="' + path.replace('$1', 'Category:封禁及禁制申诉') + '">UB 未取得</a> ';

		var api = new mw.Api();
		function getCSD() {
			api.get({
				action: "query",
				format: "json",
				prop: "categoryinfo",
				titles: "Category:快速删除候选"
			}).done(function(data) {
				$.each(data.query.pages, function(i, item) {
					document.all["adminbacklog-csd"].innerHTML = 'CSD ' + item.categoryinfo.size;
				});
			});
		}
		function getEP() {
			api.get({
				action: "query",
				format: "json",
				prop: "categoryinfo",
				titles: "Category:維基百科編輯被保護頁面請求"
			}).done(function(data) {
				$.each(data.query.pages, function(i, item) {
					document.all["adminbacklog-ep"].innerHTML = 'EP ' + item.categoryinfo.pages;
				});
			});
		}
		function getUB() {
			api.get({
				action: "query",
				format: "json",
				prop: "categoryinfo",
				titles: "Category:封禁及禁制申诉"
			}).done(function(data) {
				$.each(data.query.pages, function(i, item) {
					document.all["adminbacklog-ub"].innerHTML = 'UB ' + item.categoryinfo.pages;
				});
			});
		}
		if (typeof window.AdminBacklogCSD === "number") {
			setInterval(getCSD, window.AdminBacklogCSD);
		}
		if (typeof window.AdminBacklogEP === "number") {
			setInterval(getEP, window.AdminBacklogEP);
		}
		if (typeof window.AdminBacklogUB === "number") {
			setInterval(getUB, window.AdminBacklogUB);
		}
		getCSD();
		getEP();
		getUB();

	});

})();

Check addPortletLink success