I can only talk for Primo VE. These are the changes that I think have the most effect:
Make call number more visible (example):
prm-location-items div.tab-content-header span[ng-if=”$ctrl.currLoc.location.callNumber”] {
color: #6829ff !important;
font-size: 1.3em;
margin-left: 5px;
}
Change the display of the facets: font not bold, show both icons.
Show that there’s a pulldown menu for the search slots before starting a search
Automatically start search after change of search slot
Set focus on search box (unfortunately broken for Mac at the moment)
Use NOT_DEFINED to hide labels that are no help for the patrons
Manu Schwendener
Updates
20230109 Wrong display of Exclude facet icon on laptops
20230109 primo-explore-package
20230109 “You could use the API”
20230109 Look at others’ CSS and js
20230106 Welcome Anna Couthures-Idrizi and Jeff Peterson
You can check the changelog for updates that haven’t been mentioned in a blog post yet.
Primo views 
Thank you Manu. If you want to select only the callnumber, you can add –>
:nth-last-child(1)
See you!
Merci, Sylvain, good to know.
In this particular case, the other elements (apart from the call number in violet) are bigger because of additional instructions.