It most likely refers to Local Services Tax, which is an employment-related tax that isn’t based on your actual income amount.
It’s not a deductible local income tax, so enter it as Other (not classified).
See the pdf W-2 Frequently Asked Questions for more information. Since it’s sometimes hard to load from pdf links, here’s the actual URL: https://www.budget.pa.gov/Services/ForAgencies/Payroll/Documents/w2-faqs.pdf.
