To reproduce :
- Log-in as any user on a wiki, go in the notifications center and turn on daily notifications by email
- Do some changes on the wiki that will create notifications (for example, if the user is subscribed to a page, edit this page with another user)
- Trigger the daily email notification job
- Look at the email you received
On the top right corner of the email, you should be able to click on a link to directly access your notification preferences (see screenshot).
In practice, it's not possible, looking at the raw message, the <a> tag in the email for this particular link is generated with what seems to be a null variable.
Marking the issue as critical as it is a missing feature.