Understanding order of bash redirections, rightmost inwards

04-multi-experiments

#!/usr/bin/env bash

out="$(mktemp)"
rm -f "$out"
clear

# results in jumbled lines: printf '%s\n' "stdout" > >(cat >> "$out"; echo a >> "$out") > >(cat >> "$out"; echo b >> "$out")

# this works, from rightmost to leftmost, >>/dev/tty has no effect
echo "=== $LINENO ==="
printf '%s\n' 0 >"$out"
{
	printf '%s\n' 'stdout' #>&1
	printf '%s\n' 'stderr' >&2 # >/dev/stderr #>&2
} \
	&> >(echo-lines --stdin --prefix='&/' | tee -a "$out" >>/dev/tty; printf '%s\n' '\&' >> "$out") \
	> >(echo-lines --stdin --prefix='a/' | tee -a "$out"; printf '%s\n' '\a' >> "$out") \
	> >(echo-lines --stdin --prefix='b/' | tee -a "$out"; printf '%s\n' '\b' >> "$out") \
	2> >(echo-lines --stdin --prefix='A/' | tee -a "$out" >&2; printf '%s\n' '\A' >> "$out") \
	2> >(echo-lines --stdin --prefix='B/' | tee -a "$out" >&2; printf '%s\n' '\B' >> "$out")
wait # needed
cat -e -- "$out"
rm -f "$out"

04-multi-experiments--ubuntu-output.txt

&/A/B/stderr
&/a/b/stdout
0$
B/stderr$
\B$
A/B/stderr$
\A$
b/stdout$
\b$
a/b/stdout$
\a$
&/A/B/stderr$
&/a/b/stdout$
\&$