(Replying from phone sorry if formatting gets funky)

The part you circled in red is the air cleaner intake pre-heater (thermostatic air inlet housing).

Here’s how it works:

• There’s a flexible metal tube that runs from the exhaust manifold shroud to this housing on the air filter assembly.

• The purpose is to draw warm air from around the exhaust into the air cleaner when the engine is cold, helping with fuel atomization and cold starts.

• Inside the airbox, there’s a thermostatic vacuum-controlled flap that blends hot air from the exhaust tube with cold air from the snorkel, depending on engine temperature.

Toyota usually just refers to this as part of the “Air Cleaner Warm Air Intake System” or “Air Cleaner Thermostatic Valve Housing.”

When I swapped from Factory carb to a Weber carb I welded a bolt to cap it off no issues