Warning message (re. php) on the blog page

<a href="https://wordpress.stackexchange.com/questions/364537/<?php//echo esc_url( home_url("https://wordpress.stackexchange.com/" ) ); ?>"><?php// bloginfo( 'description' ); ?></a>

The <?php// is the problem. PHP blocks are started with <?php but the code uses <?php//. Instead, change it to <?php //, or better yet, since // is meant to comment an entire line out, use /* */ style commenting instead