Just read their website. It used to say that it's backed 1:1 by USD, period. Now it says a lot of vague things, e.g.:
>Every tether is also 1-to-1 pegged to the dollar, so 1 USD₮ is always valued by Tether at 1 USD.
So it explicitly says that it is not backed by USD, but is "valued by tether at 1 USD"
> Every tether is always 100% backed by our reserves, which include traditional currency and cash equivalents and, from time to time, may include other assets and receivables from loans
That passage probably means that they print fake dollars, then buy bitcoin with it, which rises the price of bitcoin, and allows them to claim that their reserves are "fully backed"
>Every tether is also 1-to-1 pegged to the dollar, so 1 USD₮ is always valued by Tether at 1 USD.
So it explicitly says that it is not backed by USD, but is "valued by tether at 1 USD"
> Every tether is always 100% backed by our reserves, which include traditional currency and cash equivalents and, from time to time, may include other assets and receivables from loans
That passage probably means that they print fake dollars, then buy bitcoin with it, which rises the price of bitcoin, and allows them to claim that their reserves are "fully backed"