The Python (both 2 and 3) in our build system both lack the readline module. We generally don't have much interactive use with those, so functionally it's not a major loss. However it is causing issues with unit testing as we have stuff that assumes readline is present (which it is on any sane system).
Module is now available for both Python 2 and Python 3.
I can verify that the module was not present before and when upgrading to latest cendio-build, readline is available for both Python 2 and Python 3.