Besides the obvious information (current time, boot time, serial number, etc), it also seems to tell you the recognized hardware, which can be very helpful when trying to diagnose custom build hardware issues:
The “HT/DT/IM/MT” line shows the following information:
HT (hardware type?) is 1 for a HS2/HS3 and 2 for a HS4. This is probably most important for the installed EtherNet hardware, which is different in these machines.
DT (disk type?) is showing the recognized disk type (e.g. /dev/hdb or /dev/sda/) and size. Valid values seem to be between 0 and 4.
IM (ISDN module?) is some info about how the ISDN configuration is set up.
MT (model type?) 1 for the HomeServer, 2 for the FacilityServer.