Unused global option(s) warning with latex 2022-06-01-PL2

Question

I was about to ask this question a few days ago, but at the time the site suggested this question to me and I thought that it is the same problem with mine. But now as PL2 releases, the problem in the addressed question is fixed yet mine remain, hence the question below.

Suppose that there is a package like the following:

\NeedsTeXFormat{LaTeX2e}[2022-06-01]
\RequirePackage{l3keys2e}
\ProvidesExplPackage
  {testpackage}
  {2022/06/20} {}
  {A test package}
\keys_define:nn { testpackage }
  {
    , unknown         .code:n             = {}
  }
\ProcessKeysOptions { testpackage }
\endinput

And the main document is like this:

\documentclass[11pt]{article}
\usepackage{testpackage}
\begin{document}
Text in case of empty.
\end{document}

Two days ago with 2022-06-01 PL1 one shall get

Unused global option(s):
    [11pt,11pt].

Now with PL2 it is:

Unused global option(s):
    [11pt].

However, in the previous releases, with unknown.code:n = {}, it is expected that there shouldn't be any warning here.

What is the problem here and how should one fix this?

Answer 1

This is due to a bug in l3keys2e in which I copied some (incorrect) code from an improvement to the new keyval handler in the kernel. On reflection, I've backed out the change in l3keys2e as the better plan is to migrate to the new kernel code. I will sort out a CTAN update later today to address this issue.