I learned a few years ago that HN also editorializes by dropping "world's" from titles
Before: Teens break record for world's longest kickball game
After: Teens break record for longest kickball game
Before: Teens break record for world's longest kickball game
After: Teens break record for longest kickball game
"China opens world's longest undersea tunnel"
vs
"China opens longest undersea tunnel"
It's a little unclear if it's the longest undersea tunnel in the world, or just in China