It is. It literally is.

Whenever gmail, thunderbird or office365 outlook notices a working unsubscribe link in a message, it puts its own unsubscribe link at the top of the message, right next to the address of the sender's email.

I’m sure you mean the content of the email, but we dont reach out to double opt-in users or transactional emails with an unsubscribe link, since you chose to be there.

The unsubscribe link lives near the bottom of the email along with the link to support, in clear text in a font and colour that matches the content.