updated_at

# File activesupport/lib/active_support/file_update_checker.rb, line 95
    def updated_at #:nodoc:
      @updated_at || begin
        all = []
        all.concat @files.select { |f| File.exists?(f) }
        all.concat Dir[@glob] if @glob
        all.map { |path| File.mtime(path) }.max || Time.at(0)
      end
    end