tldr: It does exactly what it says

NOTE!!! Don't mind if it says broken or incompatible, I tried it on all the versions listed and they worked.

What are christmas chests?

These are chests that will replace the normal chest textures between the 24th of December and the 26th of December.

This resource pack does nothing when its not in that time range.

go check the gallery for how it looks with and without the pack