Can you briefly summarize the purpose of the OpenFirmware device tree?
The OF device tree describes all hardware devices in the system, and the relations between those devices.
How does/would Linux use the information in the tree?
Linux would use this information to detect and configure devices.
Does it replace or supplement things like the MP table, IRQ routing table, ACPI tables, etc.?
It can replace all of these (and actually get it right :-) )
Segher