The file you're looking for is: "/assets/minecraft/textures/misc/enchanted_item_glint.png"
And yes, you can change it somewhat with a resource pack. It still moves in the way that it desires to, but you can now freely change the color and look of the base texture. It used to be FAR more restrictive than it presently is.
Also, since you didn't specify which version you're working with know that in older versions it may have a different name. I just quoted the 1.16.x version because I assumed that you're working with the most recent version of the game.
I hope that helps you.
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most of the images are broken, and also when i try to look at grar's shader guide it says im not allowed to