Examine source code of Clean YouTube Chat

{
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "version": "0.3.0",
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "48": "icon-48.png",
    "96": "icon-96.png",
    "128": "icon-128.png"
  },
  "default_locale": "en",
  "permissions": [
    "storage"
  ],
  "author": "noriapi",
  "homepage_url": "https://github.com/noriapi/clean-youtube-chat",
  "browser_specific_settings": {
    "gecko": {
      "id": "clean-youtube-chat@noriapi.addon",
      "strict_min_version": "57.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Clean YouTube Chat",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "all_frames": true,
      "run_at": "document_end",
      "css": [
        "content-scripts/content.css"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}