✨ Add add-tab action and command to link to add-tab-button

components/actions/ActionRegistry.sys.mjs

@@ -8,6 +8,7 @@ const { Action } = ChromeUtils.importESModule(
 
 const ALL_ACTIONS = [
 	// browser.tabs
+	"browser.tabs.add_tab",
 	"browser.tabs.go_back",
 	"browser.tabs.go_forward",
 	"browser.tabs.reload_page",

components/actions/content/browser/tabs/add_tab.js

@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * @typedef {import("components/actions/Action.sys.mjs").ActionDispatchEvent<T>} ActionDispatchEvent
+ * @template T
+ */
+
+const { Action } = ChromeUtils.importESModule(
+	"resource://gre/modules/Action.sys.mjs"
+);
+
+export class BrowserTabsAddTabAction extends Action {
+	static id = "browser.tabs.add_tab";
+
+	constructor() {
+		super();
+	}
+
+	/**
+	 * The name of this action
+	 */
+	get name() {
+		return "Create tab";
+	}
+
+	/**
+	 * Performs this action
+	 * @param {ActionDispatchEvent<{ url: string | string[] }>} event
+	 */
+	run(event) {
+		const { args } = event.detail;
+
+		if (!args.url) throw new Error("No 'url' argument supplied!");
+
+		const win = event.target.ownerGlobal;
+		const { gDot } = win;
+
+		const params = {
+			triggeringPrincipal:
+				Services.scriptSecurityManager.getSystemPrincipal()
+		};
+
+		gDot.tabs.createTabs(
+			Array.isArray(args.url) ? args.url : [args.url],
+			params
+		);
+	}
+}

components/commands/BrowserCommands.sys.mjs

@@ -10,7 +10,7 @@ const { CommandSubscription } = ChromeUtils.importESModule(
 	"resource://gre/modules/CommandSubscription.sys.mjs"
 );
 
-const ALL_COMMANDS = ["go-back", "go-forward", "reload-tab"];
+const ALL_COMMANDS = ["add-tab", "go-back", "go-forward", "reload-tab"];
 
 export class BrowserCommands {
 	/** @type {Window} */

components/commands/content/add-tab.js

@@ -0,0 +1,42 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const { Command } = ChromeUtils.importESModule(
+	"resource://gre/modules/Command.sys.mjs"
+);
+
+const { StartPage } = ChromeUtils.importESModule(
+	"resource:///modules/StartPage.sys.mjs"
+);
+
+export class AddTabCommand extends Command {
+	constructor(subscription, area) {
+		super(subscription, area);
+
+		this.label = "New Tab";
+		this.label_auxiliary = "Open a new tab";
+		this.icon = "add";
+	}
+
+	/**
+	 * Performs this command
+	 *
+	 * @param {{ urls?: string[], url?: string }} args
+	 */
+	run(args) {
+		let urls = [];
+
+		if (args.url || args.urls) {
+			if (args.url) urls.push(args.url);
+
+			urls = urls.concat(args.urls || []);
+		} else {
+			urls = StartPage.getHomePage();
+		}
+
+		for (const url of urls) {
+			this.actions.run("browser.tabs.add_tab", { url });
+		}
+	}
+}

components/tabs/content/browser-add-tab-button.js

@@ -6,7 +6,8 @@ class BrowserAddTabButton extends BrowserToolbarButton {
 	constructor() {
 		super();
 
-		this.routineId = "new-tab";
+		this.buttonId = "add-tab-button";
+		this.commandId = "add-tab";
 	}
 
 	connectedCallback() {