A simple editor extension to allow for direct modification to and from .asset files containing Texture2DArrays. Adds a "Tools > Texture array tools" menu option to the editor.
Normally, there is no way to directly access the textures in such files through the editor, nor can you edit the majority of their import options. The only regular option is to "extract" the individual textures of an array by hand through custom scripts, or to "merge" textures into an array by creating custom assets, also in code. Certainly a less than ideal solution, and often quite the chore to set up.
This extension resolves that problem by providing a simple, efficient, and effective window to help with the job, allowing for pretty much all possible options related to the texture array to be customised as well. I threw it together in about an hour, if that.
Alternatively, copy-paste the source from here and drop it into a file: