Built-in Anti Player ESP #826

What feature do you want to see added?

You already have great anti-Xray in the engine, I propose adding anti-ESP on top of it hiding sneaking players when they are fully occluded from the observer. The plugin AntiCheatAddition does this, but at the API level it intercepts packets and manually checks visibility, which is slower and more error-prone.
Why it would be more efficient in the engine:

• The server already decides which player to send to whom (EntityTracker) – you can simply skip the spawn there instead of cancelling already-built packets.
• You already have ray tracing and occlusion tests optimized for anti-Xray – you can reuse them to check if there are solid blocks between players.
• Zero extra overhead from listeners and mappings in plugins.
  How it could work:
  If player B is sneaking and fully occluded (no line of sight to player A), the server does not send information about B to A. The moment B stands up or is no longer blocked, they instantly appear for A. The logic hooks into the entity tracking management, with configuration in leaf.yml (disabled by default so existing servers are unaffected).
  This is a natural extension of anti-Xray and a huge help for server owners fighting wallhacks. If you have doubts about performance, I'd be happy to hear your opinion.