Comment by sznio

As for the name "impulse", I don't know - but the way this command works reminds me of interrupts.

The impulse command sends a command to the server instantly, rather than in the usual UserCmd sent to the server 30 times per second. They are used mostly for debugging, just assign #90 to your debugging function, then poke it from the console while the game is running. No need to change and potentially break the network code.