Sets ShowSecondsInSystemClock = 1 under Explorer\Advanced. Adds seconds to the taskbar clock so you can read the exact time at a glance instead of just hours:minutes. Handy for timing things, benchmarking, or just knowing the precise time. Negligible cost on modern hardware. Takes effect on the next Explorer refresh. Reversible.
MaxTweaks applies this tweak with one click and snapshots your original setting first, so you can revert it cleanly at any time. A System Restore point is offered before batch changes, and every tweak links to its official source.
Get MaxTweaksOfficial documentation: https://learn.microsoft.com/en-us/windows/win32/shell/