Gem::ConfigFile#normalize_credential_store

# File tmp/rubies/ruby-4.1.0-preview1/lib/rubygems/config_file.rb, line 881
def normalize_credential_store(value, default)
  # An environment variable can carry bytes String#downcase would reject.
  normalized = value.to_s.b.downcase

  if normalized.empty?
    default
  elsif CREDENTIAL_STORE_OFF.include?(normalized)
    false
  elsif CREDENTIAL_STORE_ON.include?(normalized)
    true
  else
    value
  end
end