FOSS gamedev and creative worlds

I know there's a way to increase/decrease walk speed, but I don't remember how. I know you go to the world in your files, go into players, then choose the player you want to increase the speed of, but I am not sure what to do next. I know I've done it before. Could someone please help?

movement_speed_walk in minetest.conf (default 4), also in Settings -> Something -> Something Else -> Something Terribly Obscure. Heh heh heh.