This property records a E54 Dimension of some E70 Stuff.
It is a shortcut of the more fully developed path from E70 Stuff through P39 measured (was measured by), E16 Measurement Event P40 observed dimension (was observed in) to E54 Dimension. It offers no information about how and when an E54 Dimension was established, nor by whom.
An instance of E54 Dimension is specific to an instance of E70 Stuff.