That's not really a secret, and it's not a new thing. This is going on for decades there.<p>What's also concerning is not only their famous incompetent micromanagement and favorisms not based on anything technical, but more importantly they are the main reason for the downfall of Perl the language. They have all the main maintainers on staff, which are famous for their toxic and destructive actions in the community, leading to the mess Perl is in now. Any improvements already designed for perl6 did not make it in, and many features were just ripped out for no other reason that it's unmaintainable for them. No types, no proper signatures, no proper object system, no macros, no jit, no advances at all in the last 15 years. No wonder everybody is leaving in disgust. As long as they are blocking any progress and backing the ongoing destruction, Booking is doomed. They are shoveling their own grave. The other major perl company started doing the same only recently, so people are leaving there also in masses.
Having a hard time to copy/paste a Google translate with the English translation, but basically the article talks about the (too) fast grow of Booking.com and all the related stress and the very old tech they are using and not willing too upgrade (Perl is mentioned). So reconsider when getting an offer from Booking.com to work there.