GR translation: fashioned of brown twilight

[Mike Jing]

V303.24-41, P308.11-29   . . . it was always easy, in open and lonely
places, to be visited by Panic wilderness fear, but these are the
urban fantods here, that come to get you when you are lost or isolate
inside the way time is passing, when there is no more History, no
time-traveling capsule to find your way back to, only the lateness and
the absence that fill a great railway shed after the capital has been
evacuated, and the goat-god’s city cousins wait for you at the edges
of the light, playing the tunes they always played, but more audible
now, because everything else has gone away or fallen silent . . .
barn-swallow souls, fashioned of brown twilight, rise toward the white
ceilings . . . they are unique to the Zone, they answer to the new
Uncertainty. Ghosts used to be either likenesses of the dead or
wraiths of the living. But here in the Zone categories have been
blurred badly. The status of the name you miss, love, and search for
now has grown ambiguous and remote, but this is even more than the
bureaucracy of mass absence—some still live, some have died, but many,
many have forgotten which they are. Their likenesses will not serve.
Down here are only wrappings left in the light, in the dark: images of
the Uncertainty. . . .

What does "fashioned of" mean here? And are these souls of
barn-swallows, or just barn-swallow-like?
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Pynchon-l / http://www.waste.org/mail/?list=pynchon-l