What is the problem?
It does not seem to matter what you type into this field.
With JS enabled, this input disappears when another option is selected.
Steps to reproduce problem
- Go to Special:Block (need to be admin)
- Attempt to submit a block with an Expiration option other than "Other time:"
Expected behavior: You are not required to type any text into the text input box under "Expiration"
Observed behavior: You are prevented from submitting until you type any text in the input