Normally is need to use a specific HTTP GET/POST variable to start remote debugging. When this setting is set to true, Xdebug will always attempt to start a remote debugging session and try to connect to vscode-php-debug plugin client, even if the GET/POST/COOKIE variable was not present.
More information on
https://xdebug.org/docs/all_settingshttps://xdebug.org/docs/remote#browser_session