Yes it just one of the detail schedules that go to the 1040 instead of going directly to the 1040.
https://www.irs.gov/pub/irs-pdf/f1040s2.pdf
It was on 2019 also. Did you have a Net Profit on Schedule C last year? You only pay self employment tax on a Net Profit of $433 or more. Maybe you had a loss last Year?
https://www.irs.gov/pub/irs-prior/f1040s2--2019.pdf
