Here's the legislation itself. It's damning. Specific, to the point, and justifies itself by claiming credible evidence and testimony exist to prove what Grusch has said.
Gist I get so far: All documentation of UAP is, by default, unclassified and set for immediate disclosure. If it's older than 25 years, it's declassified and released. Otherwise it goes through a review and at no more than 25 years it becomes public. There are outs to that of course, but MASSIVE step in the right direction. This thing is basically directly confirming what Grusch said is completely true and we are, in fact, not alone.
How does it confirm what Grusch said was true? Seems like this is just the first step towards doing that, the real test being what the classified materials released as a result of this legislation actually say.
But it justifies itself by relying on the credibility of Grusch.
Confirmation of truth will come when this legislation becomes law.
(Then again, I am a layman, foreigner to the US and I've only skimmed the PDF so don't rely on my quote!)