What's holding up this heavy horizontal beam and the rest of the void?

I'm trying to figure out how much of this void framing I can take out before I need to call the electrician to take out the electrical conduit for the former closet light, but there's a physics question I need clarified first.

What is taking the burden of holding up this horizontal beam marked in red? It's nailed from the inside of the void to the framing, so is its weight all carried by the three studs that span from floor to ceiling (marked in blue, but hard to see)? So should those three studs that span from floor ceiling come out last, after the electrician comes?

https://preview.redd.it/8oyu84pjlsof1.jpg?width=2268&format=pjpg&auto=webp&s=0a3288e9a4abed8815373d8dfd13f376750c9cea

Photos of the end of the horizontal beam from inside the void:

https://preview.redd.it/fxtdycfylsof1.jpg?width=2268&format=pjpg&auto=webp&s=d7bb254a2ea08482efecb024d8e3d891b81d870f

https://preview.redd.it/itc1xqj0msof1.jpg?width=2268&format=pjpg&auto=webp&s=3d2c91102a2fb5d76c98c6bd6ff01407c664aacc