These numbers are an index that has come from SystemEdge and is simply reflected in the branch under that name.
The meanings are explained in the Description metric under each node as confirmed in the doc here
"Description A textual description identifying the purpose of the metric and who created it".
If you wish to see these listed in one place without having to browse the UI then as with the device ids these are listed in the file /apmia/SystemEDGE/config/port1691/sysedge.mon e.g.
"FileSystem Usage (percentage)"