Examine source code of Better YouTube Subs

{
  "manifest_version": 2,
  "name": "Better YouTube Subs",
  "version": "2.1.5",
  "permissions": [
    "storage",
    "webRequest",
    "webRequestBlocking",
    "*://*.youtube.com/*",
    "tabs"
  ],
  "description": "Adds new functionality to YouTube's subscription page.",
  "browser_specific_settings": {
    "gecko": {
      "id": "Better-YouTube-Subs@Dinger1112"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "byts.js"
      ],
      "css": [
        "byts.css"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "icons": {
    "48": "icons/byts_logo.jpeg"
  }
}