What
Claude can move a long-running shell command into the background, so the command keeps going while Claude does other work. When that happens, Claude Code sends Claude a short notice about what to expect.
That notice can now include a time window. Within the window, Claude will normally be called back about the command, in a turn of its own if it has already replied. Past the window, Claude is told it may not hear about the command until you write again. Before, the notice only gave the general wording, with no window.
Why
This changes what Claude believes about when it will learn that a background command has finished. That can affect whether it waits, checks on the command or carries on with other work.