curl.1: -w filename_effective was introduced in 7.26.0

We never made a 7.25.1 release

docs/curl.1

@@ -1895,7 +1895,7 @@ The Content-Type of the requested document, if there was any.
 The ultimate filename that curl writes out to. This is only meaningful if curl
 is told to write to a file with the \fI--remote-name\fP or \fI--output\fP
 option. It's most useful in combination with the \fI--remote-header-name\fP
-option. (Added in 7.25.1)
+option. (Added in 7.26.0)
 .TP
 .B ftp_entry_path
 The initial path curl ended up in when logging on to the remote FTP