Examine source code of Youtube Run-Timer

{
  "manifest_version": 2,
  "name": "Youtube Run-Timer",
  "version": "1.0.2",
  "description": "A efficient tool used for retiming youtube videos.",
  "homepage_url": "https://github.com/Evil004/Youtube-Run-Timer",
  "icons": {
    "128": "icon128.png"
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*",
        "https://youtu.be/*"
      ],
      "js": [
        "scripts/injectYT.js"
      ],
      "all_frames": true
    },
    {
      "matches": [
        "https://www.speedrun.com/*"
      ],
      "js": [
        "scripts/injectSRC.js"
      ],
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a2ee914a-f2c7-4443-a554-263b8aebac7f}"
    }
  }
}