The /v2/plugins/providertypes and /v2/plugins/automatortypes operations are confusingly split across the user and provisioner apis. GET and DELETE are on the user api (55054), while PUT and POST are on the provisioner api (55055). It seems like DELETE should be on the provisioner api, and why not duplicate GET there as well?
This just leads to a potentially confusing user experience... at the least docs should be updated to reflect.