Yellonde, Jump Down, Area Bosses, and more!

We need skill for jump down?

As was already said multiple times, no. It is in the data as a skill, but it is a natural ability for all players and requires no work, and in fact, doesn't even appear in any skill book.

and what is the new filter?

Why would anyone know this? It's probably like the one of fabled lore that just turns curse words into asterisks, but still submits your message without problem.