Smart-IT already makes it possible to create own CSS files for rebranding and customization-purposes. (Rebranding Smart IT on the Universal Client - Documentation for Remedy with Smart IT 1.6 - BMC Documentation)
However, some customizations are not feasible with pure CSS.
When I was looking for a way to inject JS to customize the user-experience, the only solution I found was directly modifying the template inside the ‘templates.min.js’ file in the <SmartIT_Install_Dir>\ux\current\smart-it\scripts\app folder. Since this folder will be overwritten on each update/hotfix, this solution is very short-lived and time consuming to maintain.
Therefore it would be great to have a persistent JS-file for rebranding-purposes, similar to the one already existing for CSS.