All APIs agree on this, so it's not a big concern, but it was brought up in discussion with someone else, so I figured I'd file it as an editorial issue.

https://gpuweb.github.io/gpuweb/#dom-gputextureviewdimension-cube

Here, the major axes / face layer is described, but not how to map the remaining two axes to U/V coordinates within the face. There is a non-normative note that "When viewed from the inside, this results in a left-handed coordinate system where +X is right, +Y is up, and +Z is forward.", but this doesn't seem right to me, you could have +Z up, +Y right, and +X forward if wanted.

D3D11 describes this within the diagram found here: https://microsoft.github.io/DirectX-Specs/d3d/archive/D3D11_3_FunctionalSpec.htm#5%20Resources

Vulkan describes this here: https://docs.vulkan.org/spec/latest/chapters/textures.html#_cube_map_face_selection