Examine source code of rotor

{
  "manifest_version": 2,
  "author": "luv4bytes",
  "name": "__MSG_extensionName__",
  "version": "1.4",
  "description": "__MSG_extensionDescription__",
  "homepage_url": "https://github.com/luv4bytes/rotor",
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "rotor@luv4bytes.com"
    }
  },
  "permissions": [
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "src/js/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "src/js/engine.js"
      ]
    }
  ],
  "icons": {
    "48": "icons/format-rotate-90_dark.png"
  },
  "page_action": {
    "browser_style": true,
    "default_icon": "icons/format-rotate-90_dark.png",
    "default_title": "__MSG_defaultPageActionTitle__",
    "show_matches": [
      "http://*/*.png",
      "https://*/*.png",
      "file://*/*.png",
      "http://*/*.jpg",
      "https://*/*.jpg",
      "file://*/*.jpg",
      "http://*/*.jpeg",
      "https://*/*.jpeg",
      "file://*/*.jpeg",
      "http://*/*.gif",
      "https://*/*.gif",
      "file://*/*.gif"
    ]
  }
}