R puzzle

Can you guess the meaning of the following R code

"?"=`u\164f8ToI\x6Et`;'!'=prod;!{
    y<-xtabs(~?readLines())}%in%{
     z<-y[1]}&z>T##&[]>~48bEfILpu

If not (!), the explanation is provided in Robin’s answer to a codegolf puzzle.