I have added a load balancer that routes https traffic to a gerrit instance I have (to port 8080).
Using tcpdump
I do see that if I access https://foo.gerrit.bar
there is traffic with port 8080 coming into my gerrit instance.
I assume something about gerrit config that I'm missing.
I have added just the httpd reverse proxy setting:
[httpd]
listenUrl = proxy-http://127.0.0.1:8080/r/
So, it seems that this is a stupid typo and I want to keep it here in case some one else copy pastes this somewhere (aka copy-pasta).
[httpd]
listenUrl = proxy-https://127.0.0.1:8080/r/
proxy-https
and not proxy-http