For example, does
set -o nounset -o pipefail -o errexit -o noglob -o posix
apply to subshells in bash4 for any sub-version? From what I've read online and in the bash reference,
set -e, AKA
set -o errexit may apply to certain subshells such as command substitutions. The problem is that the documentation is not super transparent, and it's harder to devise appropriate tests for bash than some other programming languages.