Did it seem odd to anyone else that the Dwemer had a bell that seemed to be used to summon a dragon, and could only be activated via Shouting? As far as I know, you can't activate the thing without using a shout. Does this have any significance outside of gameplay? I'm not sure how shouting Dwemer would make any sort of sense in the TES Lore, unless Akatosh decided to gift the dragonblood to a Dwemer at some point.

Of course, it could just be a big shiny bell that just so happens to attract the attention of the dragon who had escaped to Blackreach in order to hide after the Dragon War. I just don't recall it being discussed very much.

The Dwemer are famous for using tones as magic, so I wouldn't be shocked if a dragon grew curious about something like that. Of course, that Dragon could have been living in Blackreach for some time for all we know, and using the light source drew its attention towards us.

I think that is the most likely scenario, but I don't think it was even intended as a bell in the first place. It's a big hollow sun that just so happens to ring like a bell if some jerk of a Dragonborn decides to yell at it hard enough and cause it to vibrate.

Considering it's a giant underground sun, I'd say the Dwemer probably made it as an underground Magnus. The rocks of Blackreach itself glow with Aetheric energy.

Which reminds me of a hollow earth having a internal sun theory.

The Ayleids could capture starlight to create the Welkynd and Varla stones. The Dwemer could've done the same thing with the Sun in order to illuminate Blackreach.