Examine source code of Change Webpage Fonts

{
  "author": "Kirill Bulygin",
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "128": "icons/icon_128.png"
    },
    "default_popup": "popup/main_popup.html",
    "default_title": "Page font"
  },
  "content_scripts": [
    {
      "all_frames": true,
      "js": [
        "content_scripts__run_at_end.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_end"
    },
    {
      "all_frames": true,
      "js": [
        "content_scripts__run_at_start.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_start"
    }
  ],
  "description": "Change Webpage Fonts",
  "icons": {
    "128": "icons/icon_128.png"
  },
  "manifest_version": 2,
  "name": "Change Webpage Fonts",
  "permissions": [
    "storage",
    "tabs",
    "activeTab"
  ],
  "update_url": "https://clients2.google.com/service/update2/crx",
  "version": "0.0.1"
}