Examine source code of Desktop Services for Mobile

{
  "manifest_version": 2,
  "name": "Desktop Services for Mobile",
  "version": "1.0.0",
  "description": "use some Desktop only websites on fenix",
  "permissions": [
    "storage",
    "tabs",
    "webNavigation",
    "webRequest",
    "webRequestBlocking",
    "*://www.facebook.com/*",
    "*://www.messenger.com/*",
    "*://www.new.reddit.com/*",
    "*://www.streamtape.com/*",
    "*://m.youtube.com/*",
    "*://chrome.google.com/webstore/*",
    "*://discord.com/*",
    "https://mail.google.com/mail/u/0/?view=cm&source=mailto&to=*",
    "*://lens.google.com/*",
    "*://web.whatsapp.com/*"
  ],
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "matches": [
      "*://www.facebook.com/*",
      "*://www.messenger.com/*",
      "*://www.new.reddit.com/*",
      "*://www.streamtape.com/*",
      "*://m.youtube.com/*",
      "*://chrome.google.com/webstore/*",
      "*://discord.com/*",
      "https://mail.google.com/mail/u/0/?view=cm&source=mailto&to=*",
      "*://lens.google.com/*",
      "*://web.whatsapp.com/*"
    ],
    "exclude_globs": [
      "https://mail.google.com/mail/mu/mp/152/#co"
    ]
  },
  "web_accessible_resources": [
    "page/popup.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f96308d4-b004-46a9-8545-fc0a76bfaa71}"
    }
  }
}