Examine source code of History Cleaner

{
  "manifest_version": 2,
  "name": "History Cleaner",
  "version": "0.2.0",
  "description": "Cleans browser history in set intervals, with the option of keeping some pages",
  "author": "TheNamlessGuy",
  "homepage_url": "https://github.com/TheNamlessGuy/browser-history-cleaner",
  "developer": {
    "name": "TheNamlessGuy",
    "url": "https://github.com/TheNamlessGuy/browser-history-cleaner"
  },
  "icons": {
    "16": "res/icon/16.png",
    "19": "res/icon/19.png",
    "32": "res/icon/32.png",
    "38": "res/icon/38.png",
    "48": "res/icon/48.png",
    "96": "res/icon/96.png"
  },
  "permissions": [
    "<all_urls>",
    "bookmarks",
    "cookies",
    "storage",
    "unlimitedStorage",
    "history",
    "idle"
  ],
  "background": {
    "scripts": [
      "src/options/bookmark.js",
      "src/options/opts.js",
      "src/communication.js",
      "src/historymanager.js",
      "src/background.js"
    ]
  },
  "options_ui": {
    "page": "src/options/page/index.html",
    "browser_style": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "history-cleaner@TheNamlessGuy.github.io"
    }
  }
}