Obfuscates death messages and kill messages that invisible players get. Both default to true but can be edited through gamerule commands:

/gamerule hideinvismsgs:obfuscate_invis_deaths <True/False>
/gamerule hideinvismsgs:obfuscate_invis_kills <True/False>
v1.1+
/gamerule hideinvismsgs:show_invis_team_name <True/False>
v1.2+
/gamerule hideinvismsgs:obfuscate_weapon_name <True/False>
v1.3+
/gamerule hideinvismsgs:obfuscate_dead_leave_msg <True/False>
v1.4+
/hideinvismsgs <rule/preset>