KERML — Some readonly features are intended to have changing values

Read only features (Feature::isReadOnly=true) are described as

Values of read only features on each instance of their domain are the same during the entire existence of that instance

but the libraries sometimes apply it to features with values that might be intended to change over the lifetime of an instance. For example, Clause 9.2.12.2.4 (Clock) says

A Clock provides a scalar currentTime that advances montonically over its lifetime.

but Clocks::(Basic)Clock::currentTime are readonly:

Clock { ...
  readonly feature currentTime : NumericalValue[1] {
    doc /* A scalar time reference that advances over the lifetime of the Clock. */ } ... }
BasicClock { ... readonly feature :>> currentTime : Real; }

Might be others, including features appear at the package level. For example, could check defaultClock, defaultMonitor, and defaultFrame in Clocks.kerml, Observation.kerml, and SpatialFrames.kerml, respectively.