NE_AUTH_NEGOTIATE only for https?

[Kai Sommerfeld]

Hi list,

  maybe this is a silly question, but...

  Just stumbled over the following code lines in ne_auth.c -> 
auth_register_default(...):

     if (strcmp(ne_get_scheme(sess), "https") == 0 || isproxy) {
         protomask |= NE_AUTH_NEGOTIATE;
	}

  Can somebody explain the reasons for adding NEGOTIATE only for https 
(and proxy auth), but not http?

  Thanks,
Kai.