For Primo VE customizations see https://github.com/MITLibraries/primo-explore-devenv
Contains custom CSS, HTML and Javascript for Primo VE see https://knowledge.exlibrisgroup.com/Primo/Product_Documentation/020Primo_VE/Primo_VE_(English)/030Primo_VE_User_Interface/010Primo_VE_Customization_-_Best_Practices
To gain more flexibility we use custom.js to display information on the no results page, rather than using the out of the box labels option.