If you want to add some new custom changes, you need to add a new custom php file for that page in themes/functions/ folder with name custom_tpl_articles.php, where you can add the new changes and define those to a template variable. Also you should place that variable in themes/<Current theme>/articles/ topics_info.tpl
Variables used in topics_info.tpl
{literal}{{/literal}$topic_description{literal}}{/literal} To display the topic description.
{literal}{{/literal}$topic_heading_title{literal}}{/literal} To display the topic heading title as page heading if present. Otherwise topic name is display as page heading. The data of HEADING_TITLE is defined in articles.php language file.
Sidst opdateret d. .