A subplot to both Trump’s call with Zelensky and his broader approach to Ukraine is his apparent belief that a company called Crowdstrike has ties to Ukraine and that it possibly stashed a Democratic National Committee server that was hacked during the 2016 elections. Trump would like the Ukrainians to hand this over to the US government.
This is a reference to a conspiracy theory that rolls together a couple of misperceptions.
That starts with the fact that Crowdstrike has nothing to do with Ukraine. It’s an American company whose co-founder was born in Russia but emigrated to the US as a kid. Crowdstrike was hired by the Democratic National Committee to help investigate the hacking of their email during the 2016 campaign, and Trump is disturbed by the fact that the DNC did not turn a physical server over to the FBI or anyone else. Critically, there is no server that could be hidden in Ukraine (nor would there be any reason to hide an old server there) because the DNC used a modern cloud-based distributed email setup.
But the notion Trump is alluding to is the idea that the DNC was not really hacked by Russian actors at all. Instead, that attribution was faked by the allegedly Ukraine-linked Crowdstrike, which then hid the evidence as part of a larger plot to frame both Trump and the Russian government. Trump has time and again sought to exonerate Russia of culpability for computer crimes in 2016, and his interest in Crowdstrike seems to be part of that larger agenda.