Examine source code of OldTwitch

{
  "manifest_version": 2,
  "name": "OldTwitch",
  "description": "A browser extension to bring back the old Twitch look",
  "version": "0.0.7",
  "background": {
    "scripts": [
      "js/ot-background.js"
    ],
    "persistent": false,
    "type": "module"
  },
  "permissions": [
    "storage",
    "cookies",
    "scripting",
    "webRequest"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://www.twitch.tv/*",
        "*://clips.twitch.tv/*"
      ],
      "exclude_matches": [
        "*://*.twitch.tv/*?*nooldttv*",
        "*://www.twitch.tv/p/*",
        "*://www.twitch.tv/subs/*",
        "*://www.twitch.tv/embed/*",
        "*://www.twitch.tv/popout/*",
        "*://www.twitch.tv/drops/*",
        "*://www.twitch.tv/inventory",
        "*://www.twitch.tv/embed-error/*",
        "*://www.twitch.tv/jobs/*",
        "*://www.twitch.tv/settings/*",
        "*://www.twitch.tv/privacy",
        "*://www.twitch.tv/subscriptions",
        "*://www.twitch.tv/signup",
        "*://www.twitch.tv/login",
        "*://www.twitch.tv/user/*",
        "*://clips.twitch.tv/embed*",
        "*://clips.twitch.tv/create*",
        "*://www.twitch.tv/settings",
        "*://www.twitch.tv/drops"
      ],
      "js": [
        "js/ot-config.js",
        "js/ot-main.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    },
    {
      "matches": [
        "*://www.twitch.tv/*?*nooldttv*"
      ],
      "js": [
        "js/ot-config.js",
        "js/ot-newttv.js"
      ],
      "run_at": "document_end"
    },
    {
      "matches": [
        "*://www.twitch.tv/*?*editclip*"
      ],
      "js": [
        "js/ot-config.js",
        "js/ot-newttv.js"
      ],
      "all_frames": true,
      "run_at": "document_end"
    },
    {
      "matches": [
        "*://www.twitch.tv/embed/*",
        "*://clips.twitch.tv/embed*"
      ],
      "js": [
        "js/ot-config.js",
        "js/ot-embed.js"
      ],
      "all_frames": true,
      "run_at": "document_end"
    },
    {
      "matches": [
        "*://player.twitch.tv/*"
      ],
      "js": [
        "js/ot-config.js",
        "js/ot-embed.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "html/*",
    "js/*",
    "css/*",
    "lib/*",
    "ver.txt",
    "default_config.json"
  ],
  "applications": {
    "gecko": {
      "id": "imgaming@home.lol"
    }
  }
}