Examine source code of Teams Phone Fix

{
  "description": "Fixes Microsoft Teams phone functionality by using the user agent from Microsoft Edge.",
  "manifest_version": 2,
  "name": "Teams Phone Fix",
  "version": "1.1",
  "homepage_url": "https://github.com/dev-rke/teams-phone-fix",
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "https://teams.microsoft.com/*",
    "storage",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ecb32e1d-875d-4b04-b98e-937d65765b51}"
    }
  }
}