Automatic proxy configuration URL
Supported on: Firefox 60 or later, Firefox 60 ESR or later
Registry
HKLM
Software\Policies\Mozilla\Firefox\Proxy HKCU
Software\Policies\Mozilla\Firefox\Proxy Options
AutoConfigURL text Description
If this policy is enabled, you can set the automatic proxy configuration URL. If this policy is disabled or not configured, Firefox does not use an automatic proxy configuration URL.