Publish failed due to "Could not find MODULE.bazel", not sure how to debug

[jmillikin]

I just cut rules_m4 v0.2.4 (https://github.com/jmillikin/rules_m4/releases/tag/v0.2.4), but publish-to-bcr failed:

Failed to publish entry for jmillikin/[email protected] to the Bazel Central Registry.

Could not find MODULE.bazel in release archive at ./MODULE.bazel.
Is the strip prefix in source.template.json correct? (currently it's '')

The source archive does contain a MODULE.bazel file at the top level:

$ tar -tf rules_m4-v0.2.4.tar.xz | grep MODULE
MODULE.bazel

I suspect the underlying cause is somewhere in the recently-added .tar.xz support (is it not extracting properly?), but the error email contains no logs or information so it's difficult to debug.