Author here. It's a deadline for feedback, which is why I used the word. Other comments have called it an ultimatum.
Both of those might be unnecessarily aggressive terms, but I'm not sure what another one-word term for "time something is going to get done unless you object" is.
Both of those might be unnecessarily aggressive terms, but I'm not sure what another one-word term for "time something is going to get done unless you object" is.