For anyone wanting to be unsubscribed (aka "deleted") from a mailing list using the 'mailman' software - as this list is - you can perform the action yourself. You do not need to email everyone else on the mailing list in order to do this.
1. Click the link in the footer of every email (in this case it is
https://lists.wikimedia.org/mailman/listinfo/open-glam )
2. scroll down to the 'change my settings or unsubscribe'.
3. Insert the email address you are subscribed with, then click the button.
4. On that page is a button that says "unsubscribe". Click it.
5. You will receive an email requesting confirmation, click the link.
Once complete you will receive a final email confirming that you have been successfully unsubscribed.