After migration from Parallels Helm 3 to Parallels Plesk Panel 10, forwarding domains do not have web settings.
When trying to run the pre-migration Helm 3 Compatibility Checker before performing migration from Helm 3 to Plesk 10, the following warning is shown:
Forwarding domains don't have web settings in Plesk. (All web-related settings will not be migrated.)
While Helm stores web settings for forwarding domains, forwarding domains don't have web settings in Plesk.
In Helm 3, you can turn a domain with hosting into a forwarding domain, and then go back without losing web settings. Plesk doesn't store web settings for forwarding domains, so they are ignored during the migration