where is $context['linktree'] initially set up

[EmilioGaviria]

I'm trying to change

'url' => $scripturl
to
'url' => $scripturl . '?action=portal',

but I can not figure out where is the initial set up

[All Colours Sam]

Are you using a Portal mod? most of them should take care of that for you.

$context['linktree'] gets defined in Sources/Load.php but it really depends on what you actually want to do, if you do the replacement you mention, chances are you are going to have issues on board or category index.

If you are doing a custom portal then take a look at how other portals handles the linktree

[EmilioGaviria]

I think I figured it out