Examine source code of Savelist

{
  "manifest_version": 2,
  "name": "Savelist",
  "short_name": "Savelist",
  "version": "2.1.3",
  "description": "__MSG_EXTENSION_DESCRIPTION__",
  "author": "Savelist",
  "default_locale": "en",
  "icons": {
    "16": "assets/icon/icon_16.png",
    "32": "assets/icon/icon_32.png",
    "48": "assets/icon/icon_48.png",
    "96": "assets/icon/icon_96.png",
    "128": "assets/icon/icon_128.png",
    "256": "assets/icon/icon_256.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "assets/icon/icon_16.png",
      "19": "assets/icon/icon_19.png",
      "20": "assets/icon/icon_20.png",
      "25": "assets/icon/icon_25.png",
      "30": "assets/icon/icon_30.png",
      "32": "assets/icon/icon_32.png",
      "38": "assets/icon/icon_38.png",
      "40": "assets/icon/icon_40.png",
      "64": "assets/icon/icon_64.png"
    },
    "default_title": "__MSG_SAVE_TO_SAVELIST__"
  },
  "background": {
    "page": "assets/background.html",
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "assets/content-script.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://savelist.co/*",
        "https://beta.savelist.co/*",
        "http://localhost/*"
      ],
      "js": [
        "assets/activation.js"
      ],
      "run_at": "document_end"
    }
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "permissions": [
    "tabs",
    "storage",
    "contextMenus",
    "http://*/*",
    "https://*/*"
  ],
  "web_accessible_resources": [
    "index.html",
    "assets/*",
    "build/*"
  ]
}