Wis. Stat. § 119.47: Taxes for school extension fund.

(1) If activities are being conducted under s. 119.70 (1), the board as part of the budget transmitted annually to the common council under s. 119.16 (8) (b) shall specify the amount of money required for the ensuing school year under s. 119.70 (3). The taxes so levied and collected shall constitute the school extension fund.

(2) The board may receive and expend, in addition to the tax levied and collected under s. 119.70 (3), any sums of money appropriated by the common council of the city for community services. The common council may appropriate from the city general fund or a similar fund to the school district such sums of money as the common council deems expedient.