At present the yaml schema cannot be accessed by things which need it, because it is installed as root, with read permission not available to non-root users. The chromeos-config ebuild (which uses it) cannot access this when run without 'sudo':

>>> Compiling source in /build/reef/tmp/portage/chromeos-base/chromeos-config-0.0.1-r12/work ...
 * Adding /build/reef/usr/share/chromeos-config/dts/private-files.dtsi
 * Adding /build/reef/tmp/portage/chromeos-base/chromeos-config-0.0.1-r12/work/_dir_targets.dtsi
 * 2 files found
 * Validating config:
 * - OK
Traceback (most recent call last):
  File "/usr/lib/python-exec/python2.7/cros_config_schema", line 9, in <module>
    load_entry_point('cros-config-host==1', 'console_scripts', 'cros_config_schema')()
  File "/usr/lib64/python2.7/site-packages/cros_config_host/v2/cros_config_schema.py", line 246, in main
    Main(args.schema, args.config, args.output, args.filter)
  File "/usr/lib64/python2.7/site-packages/cros_config_host/v2/cros_config_schema.py", line 227, in Main
    with open(schema, 'r') as schema_stream:
IOError: [Errno 13] Permission denied: '/usr/lib64/python2.7/site-packages/cros_config_host/v2/cros_config_schema.yaml'
Warning: Validation failed