In 25 wards, Biden received 97 percent or more of the vote, none higher than 98 percent. Based on exit polls, it is highly likely that these were overwhelmingly black districts. No other demographic could produce those numbers.
One suspects that Democratic operatives could not afford a repeat of Philadelphia 2012, when Barack Obama received 100 percent of the votes in 59 voting districts. They know that Trump is no Mitt Romney (thank God!).