impossible to use a colon in the user name with this option. The password can,
still.
-If you use a Windows SSPI-enabled curl binary and perform either Negotiate or
-NTLM authentication then you can force curl to select the user name and password
-from your environment by specifying a single colon with this option: "-u :".
+If you use a Windows SSPI-enabled curl binary and perform Kerberos V5,
+Negotiate or NTLM authentication then you can tell curl to select the user
+name and password from your environment by specifying a single colon with this
+option: "-u :".
If this option is used several times, the last one will be used.
.IP "-U, --proxy-user <user:password>"
Specify the user name and password to use for proxy authentication.
If you use a Windows SSPI-enabled curl binary and do either Negotiate or NTLM
-authentication then you can force curl to select the user name and password
+authentication then you can tell curl to select the user name and password
from your environment by specifying a single colon with this option: "-U :".
If this option is used several times, the last one will be used.