export -f

export -f

Thanks. That really does explain the feature; no other description I've seen of the little-known function-in-environment-variable feature mentions that it's for export -f . What looked like a bizarre feature now looks fairly natural.

It also explains how a Bash change is able to provide the namespace fix (adding a prefix and suffix to the environment variable name when it contains a function): Bash is at both ends of the interface.