Examine source code of eBookshelf-extension

{
  "manifest_version": 2,
  "name": "eBookshelf-extension",
  "description": "Import your eBooks to eBookshelf. Support site: Kindle, DMMブックス, BOOK☆WALKER, ebookjapan, honto.",
  "version": "0.5.1",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "permissions": [
    "storage",
    "tabs",
    "declarativeNetRequestWithHostAccess",
    "https://ebookshelf.info/",
    "https://book.dmm.com/",
    "https://read.amazon.co.jp/",
    "https://www.amazon.co.jp/",
    "https://bookwalker.jp/",
    "https://ebookjapan.yahoo.co.jp/",
    "https://honto.jp/"
  ],
  "declarative_net_request": {
    "rule_resources": [
      {
        "id": "honto-useragent",
        "enabled": false,
        "path": "rules/honto-useragent.json"
      }
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{30c1f52b-fe00-4c00-9676-5e6a615a643a}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "eBookshelf-extension",
    "default_popup": "popup.html"
  }
}