Junio C Hamano [off-list ref] writes:
We could remove it if you find it confusing.
I think the original motivation that line was added was to help
people who see "git log" (without any frills) output for the first
time not to be alarmed when they see newer things first: "In
general, the "time" flows from bottom to top", but the "time" in
that sentence is not necessarily the timestamp of either committer
nor author field.
Just to clarify, I am not defending the current wording that I did
not touch in my patch with the above. I am just giving historical
background to help _other_ people (including you) to come up with a
better wording, as I do not think of a better replacement myself.