These are the 3 most important things in the life of a beacon-node -
finalization checkpoint for security, head + time for seeing that we're
synced and working.
The order given is the expected increasing order that things should be
moving in - finalization lags head, and head lags clock - the structure
helps the user remember, but also see the pattern where time is getting
out of sync with head.
A validator would also want to know when the next action is going to be
(ie next attestation / block production) but that's for another day.
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