Originally posted by @wismill in #620 (comment)

I thought about introducing VoidAction(), to mirror NoSymbol/VoidSymbol. Because currently we also do not have an easy way to erase previous explicit actions when using RMLVO:

• NoAction() does not overwrite the previous action.
• replace key works only in the same file or after a child file.
• SetControls() kind of work if you want to break latches. But it’s ugly.

The no/void qualifiers are not very clear, but at least we would be consistent with the keysyms.