There's a HN guideline that says: If the original title begins with a number or number + gratuitous adjective, we'd appreciate it if you'd crop it. E.g. transl

There's a HN guideline that says: If the original title begins with a number or number + gratuitous adjective, we'd appreciate it if you'd crop it. E.g. translate "10 Ways To Do X" to "How To Do X," and "14 Amazing Ys" to "Ys." Exception: when the number is meaningful, e.g. "The 5 Platonic Solids." That's probably the reason why it was edited out.