Use the Hooks to debug backtrace checkbox to perform ad hoc backtraces whenever an action hook or filter is invoked.
This will help you to find where the hook is being called.
Sample trace output
Example for the_content.
wp-content/plugins/oik-bwtrace/includes/bwtrace-actions.php(608:0) bw_trace_backtrace(1) 241 0 2019-12-05T16:35:19+00:00 0.336034 0.000153 cf=the_content 9695 34 3254 6291456/6291456 256M F=583 1 <!-- wp:paragraph --> <p>Stick to the top of the blog.</p> <!-- /wp:paragraph --> 0. bw_lazy_backtrace wp-content/plugins/oik-bwtrace/libs/bwtrace.php:108 0 1. bw_backtrace wp-content/plugins/oik-bwtrace/includes/bwtrace-actions.php:609 0 2. bw_trace_backtrace(<!-- wp:paragraph --> <p>Stick to the top of the blog.</p> <!-- /wp:paragraph -->) wp-includes/class-wp-hook.php:288 1 3. apply_filters(<!-- wp:paragraph --> <p>Stick to the top of the blog.</p> <!-- /wp:paragraph -->,array) wp-includes/plugin.php:206 2 4. apply_filters(the_content,<!-- wp:paragraph --> <p>Stick to the top of the blog.</p> <!-- /wp:paragraph -->) wp-includes/post-template.php:253 2 5. the_content(Continue reading <span class="meta-nav">→</span>) wp-content/themes/twentyeleven/content.php:41 1 6. require(C:\apache\htdocs\wordpress\wp-content\themes\twentyeleven\content.php) wp-includes/template.php:724 1 7. load_template(C:\apache\htdocs\wordpress/wp-content/themes/twentyeleven/content.php,) wp-includes/template.php:671 2 8. locate_template(array,1,) wp-includes/general-template.php:168 3 9. get_template_part(content,) wp-content/themes/twentyeleven/index.php:30 2 10. include(C:\apache\htdocs\wordpress\wp-content\themes\twentyeleven\index.php) wp-includes/template-loader.php:98 1 11. require_once(C:\apache\htdocs\wordpress\wp-includes\template-loader.php) wp-blog-header.php:19 1 12. require(C:\apache\htdocs\wordpress\wp-blog-header.php) index.php:17 1
In this example we can see that the_content() is being invoked from the Twenty Eleven theme.
