What is the second bulb in the high beam/DRL chamber?

[panta_ray]

This one:



I can’t seem to get answer online about this, weirdly. What is it and how do I change that?

[DonDubber]

That's the parking/sidelight bulb, standard T10 5W type, and can be replaced by a LED with canbus compatibility.
A bit tricky to locate & remove via the access port in the back of the headlight (particularly the LH side), but plenty of YouTube videos if you Google/Bing. Here's one link Vw Golf Mk6 Headlight Dipped/Sidelight Bulb Change - YouTube.
PS: Keep bandaid box handy

[panta_ray]

I forgot to follow up this post and just remembered - thanks for the very helpful answer!