A cynical person could say that Booking.com is actively hindering Perl5 development by hiring so many (ex-)pumpkings and other people knowledgeable in Perl
OTOH, by providing them with an income, they may actually have some time to help Perl development. Open source contributers need to eat as well.
As far as I'm aware, demerphq, BooK, Abigail and Rafaël (and likely many others whose names I just currently don't have in mind) work there.
which lists about 25 people. But last what I heard is that they employ over 50 developers, so I guess not all of their employees have modules on CPAN.