There isn't normally a "Box S" on Form 1040 itself. However, if you are referring to Schedule 1 (Form 1040), line 8z (formerly line 8s), it can include other income such as jury duty pay, gambling winnings, cancellation of debt, and other miscellaneous income
For more detailed information, you can refer to the IRS guidelines on Schedule 1 (Form 1040)
If you have any more specific details or another form in mind please let us know.