V3 doc and list keys

[Fran-Rg]

Just created a cluster. etcdctl get / returns nothing whereas I've done before etcdctl put hello world

So how do I list?
I'm also confused as I can't find the HTTP API for /v3. This doc forces to use etcdtctl: https://etcd.io/docs/v3.5/dev-guide/interacting_v3/ and I don't understand how this should be read https://etcd.io/docs/v3.5/dev-guide/api_reference_v3/

I saw that previously there was a v2/keys endpoint, where is that now?

[SimFG]

you can try etcdctl get --prefix=true "".
And I have developed a tool about looking etcd data.