The string value of $TypesettingDimE determines which
symbols will be displayed above (D-4)-dimensional momenta, Dirac matrices,
metric tensors and polarization vectors. This concerns only typesetting
in the TraditionalForm output and doesn’t change the
physical behavior of those objects.
Overview, $TypesettingDim4, $TypesettingDimD.
$TypesettingDimE{}^{\wedge}