[Bug-wget] Wget cannot validate https://ftp.gnu.org?

I'm having trouble downloading tarballs from ftp.gnu.org using wget. wget --ca-certificate="$HOME/.cacert/lets-encrypt-root-x3.pem" "https://ftp.gnu.org/gnu/libunistring/libunistring-0.9.7.tar.gz; -O libunistring-0.9.7.tar.gz --2017-10-14 17:59:40--

Re: [Bug-wget] Wget cannot validate https://ftp.gnu.org?

So it looks like the behavior below is inherited from OpenSSL: $ openssl s_client -connect ftp.gnu.org:443 -servername ftp.gnu.org -CAfile ~/.cacert/lets-encrypt-root-x3.pem CONNECTED(0003) ... Verify return code: 2 (unable to get issuer certificate) However, OpenSSL also has -partial-chain