Ukraine has been getting targeting data for targets in Russia from the US and other Western countries for quite some time now. At pretty much any range the Ukies could get a weapon (mostly drones) to. The only difference is that the Ukies were using Ukie weapons, and in this case the weapons the US is allowing use of are short range and medium-short range systems like HIMARS.
Russian tools keep saying HIMARS and Excalibur are no longer effective anyway, so the threat to Russia should be minimal, right?
Also, it should be noted that this is a small counter-escalation in response to Russia’s escalation by seriously upping attacks and the threat to Kharkhiv, which is not even near being an ethic majority Russian city (or oblast).