There are still parts of Cycles that directly reference AA samples. For example, when using "branched path tracing" the there are many references to AA samples. The sample count input even has the tool tip "AA samples".

Since I'm not a developer, I'll leave the decision up to others and what to do with this.

As far as I know there's no setting in Blender called AA Samples anymore. If you find it let me know please.

Can't clean up anything without cleaning up everything. That's why it stays so messy. If we're ok with having it named different things all over the place then whatever. The vast majority of people aren't using branched path rendering on the CPU. Start changing the documentation and let the coders figure out what to do with their own deprecated names.

This is technically correct. The documentation for this could be improved, however.

See the Arnold rendering docs for example: https://docs.arnoldrenderer.com/display/A5AFMUG/Samples

The Arnold documentation has absolutely nothing to do with this. The samples setting in Blender is called Samples or better yet Render Samples and not AA Samples. This is an easy fix. Documentation should use the language used in the application (Blender in this case) for clarity and simplicity.

In T76340#922855, @Russell (russ1642) wrote:

As far as I know there's no setting in Blender called AA Samples anymore. If you find it let me know please.

Branched path tracing still refers to AA samples. The tool tip for the "Render" sample count and "Viewport" sample count is "AA samples". The total sample count section at the end of the "Sub-sampling" section directly refers to AA samples. All the tool tips for the sub-samples also refer to AA samples as well as the documentation. The python handle for the branched path tracing sample count is also "cycles.aa_samples".

As for your comment about a vast majority of people not using branched path tracing, it's probably true, especially with OptiX not supporting it.

As for why other things in the documentation and Blender refer to AA samples like adaptive sampling, I can only assume it's to accommodate for branch path tracing and because this is how Cycles works internally.

I personally believe referring to samples as AA samples can still be useful. For example, if you were to render out a scene that consisted of only direct lighting and infinitely small point lights, you could render the scene in 1 sample and get all the lighting information with no noise. Yet increasing the sample count to 8 or 32, although not helping with mitigating noise, still provides a better images due to the anti-aliasing.

As for what the documentation should refer to. I will leave that decision up to the Blender developers. However, looking at the manual page you linked, I believe AA samples is referred to in all the right places. It's only ever talked about in reference to branched path tracing with the exception of the adaptive sampling feature.

The documentation doesn't even say what AA stands for.

In T76340#923423, @Russell (russ1642) wrote:

The documentation doesn't even say what AA stands for.

It's implied with:

When using Branched Path Tracing, this changes the AA Samples which are multiplied by the Sub Samples and improve anti-aliasing.

That part could be clearer. But to me it makes sense. Once again, I will leave the decision up to the Blender developers.