Cannot reliably specify depth biases with depth24plus #6350

https://gpuweb.github.io/gpuweb/#ref-for-dom-gputextureformat-depth24plus says:

The depth component of the "depth24plus" and "depth24plus-stencil8" formats may be implemented as either a 24-bit depth value or a "depth32float" value.

https://gpuweb.github.io/gpuweb/#abstract-opdef-biased-fragment-depth says:

If format is a unorm format:

Let bias be (float)state.depthBias * r + state.depthBiasSlopeScale * maxDepthSlope.

Otherwise, if format is a float format:

Let bias be (float)state.depthBias * 2^(exp(max depth in primitive) - r) + state.depthBiasSlopeScale * maxDepthSlope.

Since it is unclear whether depth24plus is a unorm format or a float format, it is impossible to reliably specify depth biases that work. It is also not possible to query whether depth24plus is backed by a unorm format or a float format, as far as I'm aware.