Showing/hiding/placement - child, navigation, section, .../styling - icons.
Perhaps appearance model and not specific just to engineering, but generic and handled at EObjectActionProvider with extensibility.
References with eKeys shall make it easy to build such a model - class(ifier) and feature keys.
More complex with operations, but it is an edge case.
Modal actions. Cascading appearance. Ability to define Bootstrap appearance - extend?
Custom properties, e.g. to show/hide columns in issue tables.