Keystone collects the local earned income tax and the local services tax for your home township, borough, or city. You need to file a return every year and as DoninGA pointed out, TurboTax has nothing to do with these taxes, I suspect they don't wish to keep track of the rates for the 2,500 municipalities that PA has..
For the local earned income tax, the rate varies with location, from zero up to 3%. Withholding is listed in box 19 of your W2. This tax only applies to W2 income and self-employment profits (use same number that is on your PA Schedule C and include a copy). The return is all of one page, about 10 minutes to fill out once you've located your W2s for each year and copy of your PA tax return that you printed out and stored in a safe place.
