libtidy-dev binary package in Ubuntu Xenial s390x

 Corrects markup in a way compliant with the latest standards, and
 optimal for the popular browsers. It has a comprehensive knowledge
 of the attributes defined in the HTML 4.0 recommendation from W3C,
 and understands the US ASCII, ISO Latin-1, UTF-8 and the ISO 2022
 family of 7-bit encodings. In the output:
 .
  * HTML entity names for characters are used when appropriate.
  * Missing attribute quotes are added, and mismatched quotes found.
  * Tags lacking a terminating '>' are spotted.
  * Proprietary elements are recognized and reported as such.
  * The page is reformatted, from a choice of indentation styles.
 .
 Tidy is a product of the World Wide Web Consortium.

Source package