How can the standard error message for attachments be customized or modified?

Summary:

Hi,

I would like to change a default error message. How can I do this? I found the article below, but I’m not sure how to locate or edit the specific error message there.

Thank you!

The error message is coming from this restriction that I have set, which states that only PDFs should be able to be uploaded.

Is there an overview of Manage Messages?

Version (include the version you are using, if applicable):

25D