Anvil UI texture file contains large red rectangle which can never be seen

Relates to: MC-176095 MC-199660 MC-208679 MC-250985

May also relate to: MC-159560

The bug

Much like the unused buttons mentioned in MC-268376, the anvil's texture contains a massive red rectangle which is always fully obscured by the text field. Deleting this rectangle from the texture file would indicate better that it is an unused feature which is never visible, and doing so would also knock down the file size.

How to fix

Remove these pixels from the texture file. I have two fixed versions of this texture attached - one for the default textures and another for Programmer Art. Fixing this should be as easy as replacing the textures with the versions attached.