amd64 9.1, pre-wscons text colours?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

NetBSD/amd64, 9.1.

What controls the colours used for console text output before wscons
takes over?  When I build a kernel with WS_KERNEL_FG=WSCOL_GREEN and no
WS_KERNEL_BG, I see green on black, both before and after the switch
from text mode to text-in-graphics mode.  WS_KERNEL_FG=WSCOL_BLACK and
WS_KERNEL_BG=WSCOL_BLACK, and both are black-on-black.

But WS_KERNEL_FG=WSCOL_LIGHT_BROWN (I wanted yellow, that looks like
the closeset available approximation) and WS_KERNEL_BG=WSCOL_BLUE?
Once wscons switches, everything is as I would expect - but, before
that, it's white on black!

So there's clearly something I don't understand going on.  What?

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