It's usually a neon lamp, a kind of gas discharge lamp. It can run on 230V without an extra resistor, which makes it perfect for this use case. As far as I know there are no neon lamps you can use to light your room, but there are small bulbs you can buy on eBay or Amazon.
If that’s old-school it’ll be neon, modern ones get the same look with LEDs. If it’s flickering slightly, it’s neon.
Large ones are pretty rare these days, because they’re horribly inefficient at turning electricity into light. The main place you’ll still find them are as heating lamps (for things like terrariums).
The main place you’ll still find them are as heating lamps (for things like terrariums)
I thought they used incandescent lights for those, and some (like the terrarium heaters) aren't even incandescent, they're just ceramic resistance heaters that fit into an E26 base (screw-in light fixture).
They definitely use incandescent globes for heating as well. I just remember when I had fish, the shops would advertise neon heat lamps for terrariums. (I think it might have had something to do with infrared heating, but I’ve never had a terrarium so I’m kinda guessing now.)
LEDs will flicker without smoothing circuits too. Great circuits will have capacitors to smooth out the ac cycling and diode rectifiers to get power in both halves of the phase. But for $50c less, they can skip that and trust that the customer won't make a purchase decision based on an indicator light. If the item or your eyes move quickly, you'll likely catch them blinking like stop motion at 50/60hz