Minecraft wiki entry for Debug_screen, associated text: When the reducedDebugInfo gamerule is set to true, the effects of F3 + B (entity hitboxes), F3 + G (chunk boundaries), F3 + C (copying coordinates), and F3 + I (copying block/entity data) are not shown. Holding down F3 + C to initiate a crash still works as expected, as well as Ctrl + F3 + C