GratingStim.contrst parameter missing from Builder Grating component UI

OS : Debian 10
PsychoPy version: v2020.2.4post1
What are you trying to achieve?:
Use the Builder UI to set the GratingStim.contrast value on a grating using the Grating component of Builder.
What did you try to make it work?:

Looked for the Contrast field in Grating component in Builder UI.

What specifically went wrong when you tried that?:

The contrast field is not available, nor is it documented in the Appearance parameters of the Builder component docs.

We do have Opacity in the Grating component in Builder, but (per other posts here) there are slight differences between opacity and contrast, particularly regarding Michelson contrast. Perhaps I should “learn to stop worrying and use opacity for contrast?”

Thank you for your insight.