Intake vacuum lines???

Hey guys I’ve got a 91 all stock(except for exhaust) ls special integra, and I’m confused about the intake. I’ve done aftermarket intake on obd1 and up cars, but the lines on the intake (close to the throttle body) confuse me. Are they vacuum lines or what? What purpose do they serve? If I were to get an intake that didn’t have a place for them, would that be harmful? In the same vein, are there aftermarket intakes that CAN adapt to these? And yes, I have searched the forums, under “intake vacuum lines” and other variations of that. Thanks in advance!