roundtimer_override.sp goes to /tf/addons/sourcemod/scripting folder
roundtimer_override.smx goes to /tf/addons/sourcemod/plugins folder
The plugin creates the "round_time_override" cvar
Value is in seconds
Ex: rcon round_time_override 180 would set round timer to 3 minutes
Value of -1 disables round timer override, reverts back to default 10 minutes
Changes take effect on round restart
round_time_override 180
mp_timelimit 0
mp_winlimit 5