Examine source code of Booru Hotkeys

{
  "manifest_version": 2,
  "name": "Booru Hotkeys",
  "version": "0.5",
  "description": "Keyboard support for booru sites.",
  "browser_specific_settings": {
    "gecko": {
      "id": "booruHotkeys@tune"
    }
  },
  "icons": {
    "192": "icons/booki-192.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "open_in_tab": true,
    "page": "pages/options.html#options"
  },
  "content_scripts": [
    {
      "run_at": "document_start",
      "matches": [
        "*://*.donmai.us/*"
      ],
      "js": [
        "util.js",
        "dankey.js"
      ]
    },
    {
      "run_at": "document_start",
      "matches": [
        "*://gelbooru.com/*",
        "*://safebooru.org/*",
        "*://*.booru.org/*",
        "*://tbib.org/*"
      ],
      "js": [
        "util.js",
        "gelkey.js"
      ]
    },
    {
      "run_at": "document_start",
      "matches": [
        "*://*.sankakucomplex.com/*"
      ],
      "js": [
        "util.js",
        "sankey.js"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "storage"
  ]
}