Great news, up until yesterday the sender email of Wix Forum notifications was email@example.com.
From now on the sender name will be the name you choose to your forum.
In order to change it, head to the Editor, go to your Forum page, open the Forum Settings and change you Forum name under the 'Categories' tab.
You can see that notifications you're getting from this Forum now under the sender name of 'Feedback Forum'.
Please note, the email sender URL is still firstname.lastname@example.org.