FYI - This is likely the letter - I received it from taxretun@irs.gov on the third and from IRS today

If you click on the blue box for Tax Return Form, you see this same letter. The link is "https://docs.google.com/drawings/d/1sVf3yQnsAcU3gDxaW6nJEvA159nqkft8J8bSdQxaC_Y/preview"

Looking at the message source, it appears to come from New Zealand.