Examine source code of Ultimate Theme creator

{
  "name": "__MSG_extensionName__",
  "version": "0.2.2",
  "description": "__MSG_extensionDescription__",
  "browser_action": {
    "default_title": "Create your theme",
    "default_popup": "import.html",
    "browser_style": false,
    "theme_icons": [
      {
        "light": "icon-dark.svg",
        "dark": "icon-light.svg",
        "size": 64
      }
    ]
  },
  "permissions": [
    "tabs",
    "theme"
  ],
  "icons": {
    "48": "icon.svg"
  },
  "default_locale": "en",
  "manifest_version": 2
}