このツールとは？
The server time tool shows your browser (device) time and a server-based time side by side, and displays the offset between them and the network round-trip time (RTT).
なぜ使う？
Helpful for sync checks, debugging, or timestamp verification: you can see at a glance whether your device time matches the server and by how much. You can also set a target time for a countdown.
使い方
The page syncs with the server automatically. "Browser time" is your device system time; "Server/browser offset" is the difference in ms; "Network RTT" is the round-trip time in ms. Enable "Target time" to see time remaining until a chosen moment.
All times are shown in your local timezone. Server time is delay-corrected; RTT lets you see network delay.