Gem::QueryUtils#spec_loaded_from

# File tmp/rubies/ruby-3.0.5/lib/rubygems/query_utils.rb, line 307
def spec_loaded_from(entry, spec, specs)
  return unless spec.loaded_from

  if specs.length == 1
    default = spec.default_gem? ? ' (default)' : nil
    entry << "\n" << "    Installed at#{default}: #{spec.base_dir}"
  else
    label = 'Installed at'
    specs.each do |s|
      version = s.version.to_s
      version << ', default' if s.default_gem?
      entry << "\n" << "    #{label} (#{version}): #{s.base_dir}"
      label = ' ' * label.length
    end
  end
end