Start at your ILIAS root directory
mkdir -p Customizing/global/plugins/Services/UIComponent/UserInterfaceHook/
cd Customizing/global/plugins/Services/UIComponent/UserInterfaceHook/
git clone https://git.studer-raimann.ch/ILIAS/Plugins/SrUI.git SrUI- ILIAS 8.0
- PHP 7.4 - 8.0.x