Examine source code of URLR - Link shortener

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "2.0.0",
  "description": "__MSG_extensionDescription__",
  "homepage_url": "https://urlr.me/en",
  "icons": {
    "16": "icons/urlr-16.png",
    "32": "icons/urlr-32.png",
    "48": "icons/urlr-48.png",
    "128": "icons/urlr-128.png"
  },
  "permissions": [
    "tabs"
  ],
  "host_permissions": [
    "https://urlr.me/"
  ],
  "action": {
    "default_icon": {
      "16": "icons/urlr-16.png",
      "32": "icons/urlr-32.png"
    },
    "default_title": "URLR",
    "default_popup": "popup/urlr.html"
  },
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "contact@urlr.me"
    }
  }
}