We discovered in a recent HELP ticket that a spike in this metric without a spike in the connections.current metric could indicate that clients are opening closing connections before they've been accepted by the mongod listener thread, resulting in a buildup of CLOSE_WAIT connections that the listener thread has to needlessly process. If the client is aggressively opening connections to the server with a low maxConnectionTimeoutMS, that can cause a major backup of useless work on the listener thread. This whole situation requires piecing together a few different metrics, and a tooltip is a low-code way to hint towards this situation.