The correct link to the Perl Weekly Challenge is
https://perlweeklychallenge.org/. It was announced on PerlMonks, too:
see here.
Moreover, the Pull Request Challenge was succeeded by Pull Request Club. You can join the fun any time you wish.
map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]