Auto watch replied-to topics, as a default for all users?

As far as I understand, this is a user setting. As an admin, is there a way to configure this for all users?

You can configure the default (and change it for existing users) with the default_other_notification_level_when_replying site setting.

Thanks, I couldn’t find it.

Where did you try to find it? I was confused too because I expected it to be in the “user defaults” section.