The shunt topology means it behaves like a two-terminal Zener — you bias it with a series resistor from a higher supply rail, and the reference regulates by shunting current through the cathode.
Package and rework — SOT-23-3 under the hot air
The LM4040C30QDBZT comes in a SOT-23-3 package, which is about as rework-friendly as a three-pin part gets. The body is small, so it heats up fast under a hot-air station — a 300°C nozzle at moderate airflow lifts it clean in about 8 seconds. No thermal pad underneath, so no risk of hidden solder bridges.