Experimental.
Enables the replacement of CBaseCombatCharacter::SetTransmit for players, which is what actually applies holylib_networking_bind_gmodhands_to_player, holylib_networking_bind_viewmodels_to_player, holylib_networking_transmit_all_weapons, holylib_networking_transmit_all_weapons_to_owner, holylib_networking_transmit_one_per_tick, holylib_networking_transmit_newweapons and holylib_networking_transmit_onfullupdate.
It's also what pre-marks a player's hands, viewmodels and weapons as never needing a PVS check, since they're bound directly to the player instead.
If disabled, the engine's default character transmit behavior is used instead and all of the convars listed above have no effect.