17.3 Read keys from ~/.ssh/id_ecdsa, id_ed25519
17.4 Support CURLOPT_PREQUOTE
17.5 SSH over HTTPS proxy with more backends
+ 17.6 SFTP with SCP://
18. Command line tool
18.1 sync
functionality with the libssh2 backend. Presumably, this support
can/could be added for the other backends as well.
+17.6 SFTP with SCP://
+
+ OpenSSH 9 switched their 'scp' tool to speak SFTP under the hood. Going
+ forward it might be worth having curl or libcurl attempt SFTP if SCP fails to
+ follow suite.
+
18. Command line tool
18.1 sync