Examine source code of SaveForReadLater

{
  "manifest_version": 2,
  "name": "SaveForReadLater",
  "description": "__MSG_extensionDescription__",
  "version": "2.0",
  "default_locale": "en",
  "applications": {
    "gecko": {
      "id": "saveforreadlater@gmail.com",
      "strict_min_version": "84.0"
    }
  },
  "icons": {
    "48": "icons/sfl-48.png",
    "96": "icons/sfl-96.png"
  },
  "browser_action": {
    "browser_style": false,
    "default_icon": "icons/sfl-24.png",
    "default_title": "__MSG_buttonTitle__",
    "default_popup": "popup/popup.html"
  },
  "sidebar_action": {
    "default_icon": "icons/sfl-24.png",
    "default_title": "Save For Read Later",
    "default_panel": "sidebar/sidebar.html"
  },
  "page_action": {
    "default_icon": "icons/sfl-19.png",
    "default_title": "__MSG_buttonTitle__"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "browser_style": true,
    "page": "options/options.html"
  },
  "incognito": "not_allowed",
  "permissions": [
    "bookmarks",
    "contextMenus",
    "activeTab",
    "tabs",
    "notifications",
    "storage"
  ],
  "commands": {
    "_execute_sidebar_action": {
      "suggested_key": {
        "default": "Alt+Shift+S"
      },
      "description": "Show/hide the Save For Read Later sidebar"
    },
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+Shift+P"
      },
      "description": "Save It For Read Later"
    }
  }
}