The County Executive shall submit to the Council the operating and capital budget proposals as prescribed in Sections 805 and 806 of the Charter. If any revenue in the proposed operating budget is anticipated to be received from a tax or other revenue source which is not authorized by law, or from an increase in the rate of a tax or revenue source which increase requires, but has not yet received, Council approval, the County Executive shall separately identify the amount of revenue anticipated to be received when the additional revenue is authorized by law and recommended contingent appropriation amounts for expenditures proposed to be made if the County Council authorizes the tax or other revenue source or the increased rate in such tax or revenue source.