Under the "Options" menu item is an option named "Log Spawns". Turning this on is supposed to make showeq log a line whenever a mob spawns, dies and despawns. However, it was only logging deaths and despawns. There's commented-out code that says it uses opcode "OP_NewSpawn" to catch when a mob spawns, but that opcode doesn't seem to exist anymore.
I've fixed it to use the same mechanism it uses to detect when a mob is killed and removed and it logs spawns properly now.