It's a sample of bookmakers and their odds. Biden's at 4/5 (odds on, but v narrow, see 5/6), while Trump's 11/10 and 1/1 (narrow miss and evens).
In other words, they're hedging their bets because it's too close to call. That factors in every variable a bookmaker's algorithm play-book can conjure, like electoral fraud, disputed outcomes, but they only have to provide an equation for each outcome and reduce their losses.
Bookmakers are reasonable guides for where the money is headed, except when it's close like this election. Evens like Trump's betting position is pretty rare too. I lost $150 in AC though, so bit of an amateur take.