yurisuika

The reason I suggest that this is probably intended to be the same as the Wax On is because the value is the exact same as the Electric Spark. Thus it would appear as though when created this value was copy-pasted from the wrong Glow particle. This is just my assumption, but being that there is nothing to suggest electricity or anything similar in the Wax Off, it seems pretty obvious that something along the lines of this must have occurred. I have done the same thing many a time myself, copying something from the wrong file when it is in a set. Perhaps it was intended to be something unique and the copy-paste was just part of the setup, but the value was never changed in the end.

20w49a, as well as on the front face of the horse.

A tintindex may or may not be a single hardcoded value. Both oak leaves and birch leaves have a tintindex, for example, but the former uses a calculation based on a colormap and the other uses a single hardcoded decimal value.

I am sorry to say, sir, but this is still unresolved, and it will not be resolved until the entity and sprite models have overlay textures added to them.

Here are two screenshots using the latest vanilla textures of 1.15 Pre-2 and with a resource pack. You can clearly see that the entire leather horse armour is dyed. This should not be the proper way the texture is intended to be used. With the human armours both the sprites and the models have overlay textures to write over the dyed layer with undyed pixels. This, however, was never added to the leather horse armours.

As seen in the extracted 1.15-pre2.jar itself, there are still no overlay textures. While the sprite can be fixed by resource pack creators, the entity model cannot be.

Still present as of latest pre-release. This also affects the normal oak trapdoor as well.

They probably have just not coded in the overlay textures yet. It is clear from the textures that they intend to add the overlay, otherwise the vanilla textures would not make sense.