Hi, 16243 add property API to RPackage https://pharo.fogbugz.com/f/cases/16243 testPropertyAtPut | testValue package | testValue := Date today. package := self class package. package propertyAt: #testKeySelector put: testValue. self assert: (package propertyAt: #testKeySelector) equals: testValue. package removeProperty: #testKeySelector. self assert: package properties isNil. (and yes, the property API should be a trait…)