The settled registration (status is ready).
The model override, or null for the server's default.
A short reason, set only while status is failed.
The coarse failure class behind error, set only while status is
failed. null from a Personal Server that predates the class
(personal-server-ts before the status route).
When the last compute finished, or null while pending.
Local version of the derived record the last compute wrote.
The derived record the Personal Server wrote and the builder just read.
askPersonalServer's answer.