Tenebris
Minecraft map mods (or X-Ray resource packs) are convenient and good. However, one of their features is that entities outside your field of vision can be seen. Some players use this feature to gain an advantage in PVP or war.
That's why Tenebris is needed. Tenebris checks if an entity is outside player's field of vision, and if it is, it does not send it to the player. The client simply sees it as a non-existent entity and does not process it.
Tenebris is not complicated. Just add it to your server plugin file and experience effective anti-X-Ray!
