Examine source code of Booru Shinshi

{
  "manifest_version": 2,
  "name": "Booru Shinshi",
  "version": "0.12.2",
  "applications": {
    "gecko": {
      "id": "{634d6532-4ae5-4a94-a232-37e81d4d7eec}"
    }
  },
  "description": "ボール紳士：紳士のような（?）ボール (Booru) サイト間をエレガントに渡り歩く。Just one-click to download image with comprehensible filename & auto classify from Booru page, or search across different Booru sites.",
  "icons": {
    "256": "img/icon.png"
  },
  "page_action": {
    "browser_style": true,
    "default_icon": {
      "256": "img/icon.png"
    },
    "default_title": "Download this image"
  },
  "browser_action": {
    "default_title": "Booru Shinshi"
  },
  "options_ui": {
    "page": "dist/options_ui.html",
    "browser_style": true,
    "open_in_tab": false
  },
  "background": {
    "scripts": [
      "dist/background.js"
    ]
  },
  "content_scripts": [
    {
      "run_at": "document_start",
      "matches": [
        "*://chan.sankakucomplex.com/*",
        "*://yande.re/*",
        "*://konachan.com/*",
        "*://konachan.net/*",
        "*://danbooru.donmai.us/*",
        "*://betabooru.donmai.us/*",
        "*://gelbooru.com/*",
        "*://safebooru.org/*",
        "*://booru.allthefallen.moe/*",
        "*://tbib.org/*",
        "*://rule34.xxx/*",
        "*://rule34.paheal.net/*",
        "*://rule34.us/*"
      ],
      "js": [
        "dist/content.js"
      ],
      "css": [
        "dist/content.css"
      ]
    }
  ],
  "web_accessible_resources": [
    "img/favicons/*"
  ],
  "permissions": [
    "tabs",
    "storage",
    "downloads",
    "unlimitedStorage"
  ]
}