Drift modifiers input is not documented.

[PDoakORNL]

But obviously aren't to be deleted #1551 #1531

To Reproduce Create bug with drift modifiers, try and figure out how they are actually supposed to work and what legal input is.

Expected behavior A clear and concise description of what you expected to happen.

System:

• system name [e.g. fusiont5, summit]
• modules loaded [e.g. output of module list]
• other systems where this is reproducible [e.g. "my laptop", "none"]

Additional context Add any other context about the problem here.