wget -q https://zwoggel.net/ca.zwoggel.net.crt
= To install it in linux system wide= copy it to /etc/ssl/certs/ and trigger the certificate update process. With debian:
update-ca-certificates
But for debian you could also use the method described in ZwoggelDebian.
sudo keytool -import -trustcacerts -alias zwoggel.net -file <PATHTO>/ca.zwoggel.net.crt -keystore lib/security/certs
using default password “changeit” in the jre's home directory.