What are these host keys I see in sshd_config in Debian?

In debian 8 and Raspbian 8 alike, in the /etc/ssh/sshd_config file I see uncommented Hostkey entries that look like this

(commented) HostKeys for protocol version 2

HostKey /etc/ssh/ssh_host_rsa_key

HostKey /etc/ssh/ssh_host_dsa_key

HostKey /etc/ssh/ssh_host_ecdsa_key

HostKey /etc/ssh/ssh_host_ed25519_key

This is strange to me, as I do not remember my CentOS box nor my Slackware box having these preconfigured. When I connect through ssh through my Slackware box I use a generated key with a password in it....are these "HostKeys" I see for something else, like the fingerprint ID? In my slackware box I see several of these keys in the directory but the entries are commented in the sshd_config file.