[Suggestion] External layers / Shared layers across textures

[Estecka]

Detailed description of your suggestion

Context:

I've often needed to create multiple variants of the same textures, things like the same character wearing different clothes, or inversely, different characters wearing the same clothing. Blockbench's ability to hold multiple textures for the same model would be helpful in theory, but in practive I never use it. I rely a lot on layers, and my different textures can be boiled down to different arrangements of the same layers. If I want to make some adjustments to one of these layers, copying the changes over to the other textures would be very tedious.

Instead, I prefer using a single texture, that contains all the layers for all the texture variants. That way I only need one copy of the common layers, and I can still easily switch between variants by simply toggling a few layers on or off. The downside of that being that I need to manually export each variant to their own file, but I find that easier to work with than the alternative.

Suggestion:

What I'd like some way to share layers across multiple textures, so that changes to one texture would automatically carry over to the others.

The implementation I think would be the most intuitive is an option to have some layers be saved to and loaded from external files, similarly to how the texture list already works; then I could simply have the shared layers point to the same file.

External layers is something I already wished for for other reasons, mainly because it would make versioning more granular.
Theoretically that should also make it possible to share layers across projects; although I don't have a concrete use case for this yet, this sounds like an equally powerful tool, and something I could end up doing eventually.