Good catch. I think it's because support for PostgreSQL 10 was added in a later version. If the version is not known to the driver it will fall back to the oldest.
For me it seems the documentation is not up to date as the named folder sturcture is not existing in the EnterpriseDB installer installed version or in the official sources.
I also looked whether there is something like an extra psql module to download, but have not found anything.