CapabilityDefaultsHelper : if you by accident implement this interface in your CapabilityTypeModule implementation (or in any other module visible to Spring) you can implement the method:
@NotNull
CapabilitySet addDefaultCapabilities(@NotNull CapabilitySet capabilitySet);
Then you can auto detect your capabilities.
Despite what the prototype suggests, all known implementations of this interface just add capabilities in place to the capabilitySet and return it instead of creating a copy.
We don't want to let the users know that, IMO 
It's not our invention (CapabilityDefaultsHelper), we just used it as it's quite convenient.
http://confluence.atlassian.com/display/BAMBOO/Capability+Type+Module