Examine source code of groove.id

{
  "applications": {
    "gecko": {
      "id": "addon@grooveid.com"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "all_frames": true,
      "js": [
        "content.js"
      ],
      "matches": [
        "https://*.groove.id/_cors",
        "https://*.grooveid.net/_cors",
        "https://*.grooveid.net:8443/_cors",
        "https://*.slack.com/*",
        "https://*.dropbox.com/*",
        "https://*.twitter.com/*",
        "https://admin.webex.com/*",
        "https://*.concursolutions.com/*",
        "https://*.google.com/*",
        "https://login.microsoftonline.com/*",
        "https://office.com/*",
        "https://www.office.com/*",
        "https://account.activedirectory.windowsazure.com/*"
      ]
    },
    {
      "js": [
        "channel.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_start"
    }
  ],
  "description": "With this extension installed, you can do even fancier things with groove.id",
  "icons": {
    "128": "icon_128.png"
  },
  "manifest_version": 2,
  "name": "groove.id",
  "permissions": [
    "tabs",
    "activeTab",
    "cookies",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "https://*.groove.id/*",
    "https://*.grooveid.net/*",
    "https://*.grooveid.net:8443/*",
    "https://*.concursolutions.com/*",
    "https://*.slack.com/*",
    "https://*.dropbox.com/*",
    "https://*.twitter.com/*",
    "https://admin.webex.com/*",
    "https://*.google.com/*",
    "https://login.microsoftonline.com/*",
    "https://*.login.microsoftonline.com/*",
    "https://account.activedirectory.windowsazure.com/*",
    "https://office.com/*",
    "https://*.office.com/*"
  ],
  "version": "2019.1025.915.2648"
}