Configure Contact Form 7 to send non-default filetypes

This seems like it must be simple. But I do not see where I can configure Contact Form 7 to allow me to email a .zip file. The form works well by itself. It works well sending a .pdf attachment. But I cannot send a .zip attachment.

I see loads of posts explaining about the default file types:

Contact Form 7 has default restrictions for file types for security reasons.

Contact Form 7 applies default restrictions for file type and file size when you do not set the filetypes: and limit: (file size) options explicitly. Default acceptable file types (extensions) are: jpg, jpeg, png, gif, pdf, doc, docx, ppt, pptx, odt, avi, ogg, m4a, mov, mp3, mp4, mpg, wav, and wmv. Default acceptable file size is 1 MB (1048576 bytes).

https://contactform7.com/2009/11/24/file-uploading-and-attachment/

I see loads of posts explaining how to lift the restriction for UPLOADING files:
I might do something like this:
[file myfile filetypes:zip]

I even see posts from people who seem to have had the same problem as me, and they seem to have solved it:
plugin-contact-form-7-files-sending

But they do not explain where they made the change to allow a non-default filetype like “zip” to be used as an attachment. Where can I set this?