what is the name of this lightbulb

Perhaps Halogen 100W.

Not sure what the 6V is. Maybe "GV", Walmart's Great Value. They have these bulbs.

Or GY, for GY-type pin-lamp base. There are different pin spreads under the GY family, so make sure you have the right one. See also https://en.wikipedia.org/wiki/Bi-pin_lamp_base (as suggested in the comments by brhans)

Here's an overview for any interested readers:

From https://patentimages.storage.googleapis.com/b7/73/19/c0beebbacf9410/US8888332.pdf

Here's a link to the above bulb:

https://www.wayfair.ca/HeathZenith--100W-Halogen-Replacement-Bulbs-SL5591A2A-L338-K~HEH1120.html?refid=GX185650380210-HEH1120&device=c&ptid=266190925378&targetid=pla-266190925378&network=g&ireid=3346990&gclid=CjwKCAjwxuuCBhATEiwAIIIz0aQYFiIG9NljPwFZQVfdkUB0BdFae-QcAWGvnQl_A0sqbbXqZTJJHxoCRPUQAvD_BwE