Brazil's former president Jair Bolsonaro is set to rally supporters in Rio de Janeiro on Sunday in defense of freedom of expression, which he says is under threat in the country, as tech tycoon Elon Musk faces a legal showdown there over claims of censorship and disinformation.The judge, Alexandre de Moraes, has waged a crusade against disinformation, especially attempts by far-right supporters of Bolsonaro to discredit Brazil's voting system.