Which governmental activities stop (or continue) during a U.S. Government shutdown?
Here’s the Labor department’s plan:
https://www.dol.gov/dol/Contingency_Plan.pdf
And here’s the Internal Revenue Service’s plan:
https://home.treasury.gov/system/files/266/IRS-Lapse-in-Appropriations-Contingency-Plan_Nonfiling-Season_2018-12-03.pdf
Other plans:
https://www.whitehouse.gov/omb/information-for-agencies/agency-contingency-plans/