What is the Unsubscribes list under Email Templates?

It lists the email addresses that clicked the unsubscribe link at the bottom of an email from your store.

1. Go to Settings → Web Settings → Email Templates.
2. Click Unsubscribes at the top right.

Each row shows the Email, when they Unsubscribed, and the Source. Use Search by email… to find someone.

If a customer unsubscribed by mistake, click Re-subscribe, then confirm. The address is removed from the list.

This list is a record for you. Being on it does not stop Wcart from sending emails to that address. Your newsletter list is separate and is managed under Marketing → Newsletter Subscribers.