Debug. You wouldn't need this...
When enabled, the next entity transmit cache update dumps its full state to the console: the full-check entity list, the PVS entity list, the never-/always-transmit bitmasks, the holylib_networking_areasplit area lists, the entire entity cache and, if holylib_networking_fastcharactertransmit is enabled, every player's bound hands/viewmodel/weapon handles.
It automatically resets itself back to 0 again after the dump, so it only triggers a single dump per toggle.