One of the first links on that page is a document titled "INDEPENDENT AUDITORS' REPORT ON THE CONSOLIDATED RESERVES REPORT"

https://assets.ctfassets.net/vyse88cgwfbl/2xJyKdUKicdRUWpC9b...

Who are bdo.it ?

Not one of the first four auditing companies i'd call or trust.

BDO is literally the number five accounting firm globally; so, yeah, not the top four, but ...

BDO is a legit company, though not a "Big-4", I think most would consider them top-10 for audit without any qualms. It's much more reputable than some of the firms that Tether had been trotting out in the past.

A reserves report is not an audit