How can I turn off WP_DEBUG_LOG messages coming from a specific plugin or theme?

by

You are probably annoyed by too many DEBUG messages of unrelated plugins. The best solution I found for this was to turn on DEBUG logging only if a certain URL is matched:

if (strpos($_SERVER['QUERY_STRING'], 'page=myplugin') !== false)
   define('WP_DEBUG_LOG', true);
else
   define('WP_DEBUG_LOG', false);