False positive in SketchupRequirements/RubyCoreNamespace:

[thomthom]

Analysing extension...
Inspecting 141 files
.........................................................................................................................E...................

Offenses:

[extension-name]/lib/gems/rubyzip/lib/zip/filesystem.rb:628:7: E: SketchupRequirements/RubyCoreNamespace: Do not modify Ruby core functionality. (https://github.com/SketchUp/rubocop-sketchup/tree/main/manual/cops_requirements.md#rubycorenamespace)
      include FileSystem
      ^^^^^^^

141 files inspected, 1 offense detected

The vendored file looks roughly like this:

module ExtensionNamespace
  require 'zip'
  # ...

  module Zip

    module FileSystem
      # ...
    end

    class File
      include FileSystem
    end
  end
end

The cop thinks that File is Ruby's own ::File class while in reality it's ExtensionNamespace::Zip::File.

[thomthom]

This might not be a false positive after all. Need to check how Ruby resolves the File class.