There is a typo in curl man page.
Here is a link to the typo:
https://github.com/bagder/curl/blob/master/docs/curl.1#L1678
Here is the faulty text:
"When saving output to a file, this option tells curl to store certain file
metadata in extened file attributes."
"extened" should be replaced with "extended".
Thanks! Fixed and pushed now as commit 9c2853f2aecb53.