Can someone please explain the process behind tp=1 for the mod positions preview ,
I found the module output which is called from templates/system/html/module.php
and I know that the style is being forced if site is accessed via tp=1 var https://github.com/joomla/joomla-cms/blob/7d55d68cfbfe2b86589f2df9aab1771afce4fab0/libraries/cms/module/helper.php#L229
what I assume is happening is that when accessed via tp=1 the site is forced to use system template but I am looking for actual process and cant find it.
$attribs['style'] .= ' outline';
$attribs['style'] .= ' customoutline';
and have my customoutline chrome in modules.php I still get only the mods published on that page , not all module positions.
So can anyone please explain or show me where( what file ) the process is located.