root@fb7530:~# uci set test.@test[0].test=$'foo\nbar\t123\015'
root@fb7530:~# uci show test
test.@test[0]=test
test.@test[0].test='foo
'ar	123
root@fb7530:~# uci commit test
root@fb7530:~# cat /etc/config/test

config test
	option test 'foo
'ar	123

root@fb7530:~#