https://github.com/Xelitan/Free-Pascal-port-of-Brotli/Add SimpleBrotli to your uses, then:
BrotliDecompressFile('alice.br', 'alice.txt');
also available:
function BrotliDecompressStreams(InStr, OutStr: TStream): Integer;
function UnBrotli(const Compressed: AnsiString): AnsiString;