Our courts call it “hearsay” and it is inadmissible in any court in the country.
It is a political process in a court of democRAT circus clowns.
If I was Trump, I would want to know who secretly changed the whistleblower form to allow hearsay and third-party gossip just in time to allow this Ukraine whistleblower to file their complaint against Trump. The whistleblower law doesn't not allow for that. The democRATS and Deep State and manipulating the system to get want they want as an outcome.
They are trying ram a square peg into a round hole no matter what it takes.