What is it?

[Notimetolooz]

Of course removing the CRT and putting it back in a color set this size is quite a project.
Since you haven't worked on vintage color set before and don't have the equipment needed to adjust them, I recommend that you, as the best as you can, not remove the yoke assembly and other items on the CRT neck. There are many mechanical adjustments there. Hopefully most of those items can be unplugged from the chassis.
I remember seeing a video online a couple of years ago where someone had tried the "CRT in the sun with wood wedges" to remove a cataract. It ended with a plastic garbage can filled with broken CRT glass. You have to be very careful if you use wedges, the CRT always has about 15 lbs per square inch atmospheric pressure on it, it can't take much more, especially if any force is applied to a small area like a wedge.
https://www.earlytelevision.org/Deks...ug_harland.htm