The designers on my project actually designed such a non-telling unprofessional-tone “oops” error page.
Colleague implemented it like that, but on review we agreed it’s just bad, and suggested/implemented an actually useful, professional error page.
It baffles me how people can implement actively useless stuff like that. And it even showed up in my team. I was somewhat surprised. I’m glad I’m Lead, and have direct communication with the customer. Two ways to prevent and improve things like that. At least in my projects.