Ack mail

You're referring to the "ACK" mail!

ACK is a type of email that is often used in a humorous or ironic way to acknowledge receipt of an email, but not necessarily to indicate that the sender's request or inquiry has been acted upon.

The term "ACK" is short for "acknowledgment," and it's commonly used in computing and technology contexts to confirm that a message or request has been received. However, in email culture, "ACK" has taken on a more playful meaning, often used to acknowledge receipt of an email without committing to taking any action or providing a substantive response.

For example, if someone sends you an email asking for help or requesting information, you might respond with a simple "ACK" to acknowledge that you've received the email, without necessarily promising to provide a detailed response or solution.

So, if you receive an "ACK" mail, it's likely that the sender is just acknowledging receipt of your email, rather than indicating that they're taking action or providing a substantive response.