KERML_ — direction, semantics

Feature direction (Feature::direction:FeatureDirectionKind) is described as

in, out, inout: Specifies the direction of a feature, which determines what is allowed to change its values on instances of its domain:
-in: Things "outside" the instance. These features identify things input to an instance.
-out: The instance itself or things "inside" it. These features identify things output by an instance.
-inout: Both things "outside" and "inside" the instance. These features identify things that are both input to and output by an instance.

but this semantics is not math/modeled and depends on Kernel for instances changing over time.

Defer to RTF

The FTF considers this issue to have merit, but, due to lack of time, is deferring it to a future RTF.