Delivra automatically adds a list-unsubscribe header to your mailings.
To check, you can send a mailing to your Gmail from our system (or check a previous received mailing).
Once opened click the drop down next to the recipient name: (it will say "show details" if hovered over).
Note the unsubscribe option that is linked:
We don't recommend actually unsubscribing from your own list unless you are using a purely test email.