Today you get a Error Messages for Missing Permissions which don't say which for which entity it is missing.
If you look at the Protocol you get to see this. At least the entity name would be nice.
Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=9.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: Principal user (Id=4ffe5c8d-a989-e711-80e4-3863bb357cf8, type=8) is missing prvCreatenew_bpf_3eb99e4b67bf421498468987929593b6 privilege (Id=a18c95e4-c39f-4e6e-826f-016fb291403e)
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