Examine source code of GSConnect

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "8",
  "homepage_url": "https://github.com/andyholmes/gnome-shell-extension-gsconnect/wiki",
  "default_locale": "en",
  "browser_action": {
    "default_title": "__MSG_extensionName__",
    "default_popup": "popup.html",
    "default_icon": "images/gsconnect.svg"
  },
  "applications": {
    "gecko": {
      "id": "gsconnect@andyholmes.github.io"
    }
  },
  "background": {
    "page": "background.html"
  },
  "permissions": [
    "nativeMessaging",
    "tabs",
    "contextMenus"
  ],
  "icons": {
    "16": "images/gsconnect.svg",
    "22": "images/gsconnect.svg",
    "24": "images/gsconnect.svg",
    "32": "images/gsconnect.svg",
    "48": "images/gsconnect.svg",
    "64": "images/gsconnect.svg",
    "128": "images/gsconnect.svg",
    "256": "images/gsconnect.svg"
  }
}