data-

Custom data attributes are intended to store custom data private to the page or application, for which there are no more appropriate attributes or elements. 3.2.5.7. Embedding custom non-visible data with the data-* attributes

Links about data-

1. A Complete Guide to Data Attributes | CSS-Tricks

   posted on February 18, 2020 by Chris Coyier

   Everything you ever wanted to know about data attributes in HTML, CSS, and JavaScript.

   

Code sample

<h3 data-author-id="bob">
  Bob
</h3>