The outlines of the deal, which is not yet finalized, have been discussed between ministers and senior officials of the three nations, unnamed sources told the Financial Times. It may include Patriot systems being sent from Israel to the U.S. and then to Ukraine.
Systems Israel bought and later also upgraded to GEM+.
And with a major portion of US military aid grants coming with the condition that the purchased equipment come from US contractors you can argue which funding bucket it came from, but in all practicality Israel bought US systems with aid money granted from the US and then where willing to give the old systems they intended to decommission to someone the US is aiming to support.
It really is just US aid to Ukraine with an Israeli sticker on it in that sense.