If true (a complaint is just an allegation) this would be the second “smoking gun.”
As evidence by the conflicting lies by Mulvaney & Trump, the President has a real problem explaining why he had Mulvaney put a stop on the money other than to create leverage for the call. The Administration had twice previously advised Congress the money was coming (both in May) only to have Trump unilaterally hold it up one week before the call.
The second so-called smoking gun comes in the alleged actions they may have taken AFTER to conceal their activity. They will claim general housekeeping or something similar but if the report is true the data was likely moved on its own, which will create the same difficulty explaining why it was done.
Add to this the Barr-led DOJ rejecting a criminal referral with probable caste of a campaign violation and you have a Warergate-esque scandal that would potentially bring down any “real world” administration. (This not the “real world” though because the GOP is backed into a corner)