The location of the original password files. If this is not /etc, the files are symlinked from this location to /etc. The primary motivation for this is an immutable /etc, where we cannot write the files directly to /etc. However this an also serve other use cases, e.g. when /etc is on a tmpfs.

if immutableEtc && !config.services.userborn.static then "/var/lib/nixos" else "/etc"