Why Are Some Inspector Fields Read-Only?

Hi! I'm relatively new to programming and Unity, so please expect some ignorance.

I wanted to make the volume opacity on a Light 2D Experimental component oscillate between two values, but when I get a reference to the component via script and try to change it, it says that volume opacity is read-only.

Why is the volume opacity read-only while I can access the intensity of the light directly in the same way? It seems arbitrary to me what I can and can't access via script. Also, is there a way to change the volume opacity via script?

I appreciate you all!