Examine source code of MSync

{
  "manifest_version": 2,
  "name": "MSync",
  "version": "4.0.0",
  "description": "Extension to syncronize websites and MChad desktop app",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "content_scripts": [
    {
      "run_at": "document_end",
      "matches": [
        "*://www.youtube.com/watch?v=*"
      ],
      "js": [
        "InjectBtnYoutube.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://www.youtube.com/live_chat*"
      ],
      "js": [
        "InjectBtnYoutubeLC.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "https://www.youtube.com/live_chat?v=*"
      ],
      "js": [
        "InjectYoutubeChatHome.js"
      ],
      "all_frames": true
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://www.twitch.tv/videos/*"
      ],
      "js": [
        "InjectBtnTwitch.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://www.twitch.tv/popout/*/chat*"
      ],
      "js": [
        "InjectBtnTwitchLC.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://www.twitch.tv/*"
      ],
      "js": [
        "InjectBtnTwitchLive.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "https://www.twitch.tv/embed/*/chat?*"
      ],
      "js": [
        "InjectTwitchChatHome.js"
      ],
      "all_frames": true
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://live.bilibili.com/*"
      ],
      "js": [
        "InjectBtnBiliBiliLive.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://www.bilibili.com/video/*"
      ],
      "js": [
        "InjectBtnBiliBili.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "https://player.bilibili.com/player.html*"
      ],
      "js": [
        "InjectBiliBiliEmbed.js"
      ],
      "all_frames": true
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://www.nicovideo.jp/watch/*"
      ],
      "js": [
        "InjectBtnNND.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "https://embed.nicovideo.jp/watch/*"
      ],
      "js": [
        "InjectNNDEmbed.js"
      ],
      "all_frames": true
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://live2.nicovideo.jp/watch/*",
        "*://live.nicovideo.jp/watch/*"
      ],
      "js": [
        "InjectBtnNNDLive.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "https://twitcasting.tv/*/embeddedplayer/*"
      ],
      "js": [
        "InjectTwitcastEmbed.js"
      ],
      "all_frames": true
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://twitcasting.tv/*/movie*",
        "*://*.twitcasting.tv/*/movie*"
      ],
      "js": [
        "InjectBtnTwitcast.js"
      ]
    },
    {
      "run_at": "document_end",
      "exclude_matches": [
        "https://twitcasting.tv/*/embeddedplayer/*"
      ],
      "matches": [
        "*://twitcasting.tv/*",
        "*://*.twitcasting.tv/*"
      ],
      "js": [
        "InjectBtnTwitcastLive.js"
      ]
    }
  ],
  "permissions": [
    "*://www.youtube.com/*",
    "*://twitcasting.tv/*",
    "*://*.twitcasting.tv/*",
    "*://www.twitch.tv/videos/*",
    "*://www.twitch.tv/*",
    "*://live.bilibili.com/*",
    "*://www.bilibili.com/video/*",
    "*://www.nicovideo.jp/watch/*",
    "*://live2.nicovideo.jp/watch/*",
    "*://live.nicovideo.jp/watch/*",
    "https://repo.mchatx.org/"
  ]
}