https://getkirby.com/docs/developer-guide/configuration/folders
In site.php
in the root of the installation it’s possible to change the roots like this:
$kirby = kirby();
$kirby->roots->snippets = $kirby->roots()->index() . DS . 'snippets';
$kirby->roots->plugins = $kirby->roots()->index() . DS . 'plugins';
Register own roots
It’s also possible to add own custom roots, like this…
site.php in root of your installation:
$kirby->roots->bricks = $kirby->roots()->index() . DS . 'bricks';
Get it in a snippet/template/pattern like this:
echo kirby()->roots()->bricks();
It can be a perfect way to customize the urls for a plugin.
(I did not get the same thing to work with urls)