18.2 glob posts
18.3 prevent file overwriting
18.4 simultaneous parallel transfers
+ 18.5 UTF-8 filenames in Content-Disposition
18.6 warning when setting an option
18.8 offer color-coded HTTP header output
18.9 Choose the name of file in braces for complex URLs
Using the multi interface would also allow properly using parallel transfers
with HTTP/2 and supporting HTTP/2 server push from the command line.
+18.5 UTF-8 filenames in Content-Disposition
+
+ RFC 6266 documents how UTF-8 names can be passed to a client in the
+ Content-Disposition header, and curl does not support this.
+
+ https://github.com/curl/curl/issues/1888
+
18.6 warning when setting an option
Display a warning when libcurl returns an error when setting an option.