I think the user wants to debrand his application so that there are no or few references to QuickBase in the browser chrome and perhaps introduce his own branding and logos. To a limited extent you can customize the headers and footers of your application but it will not allow you to white label your application. See:
Dashboard | Settings | BrandBut I might have another answer to this question in a week's time because at the recently conduced Empower 2016 conference E encouraged me to hack the branding: "Dan, why don't you apply your considerable talents and out of the box thinking to hack branding? Our users would love this!" I could not get this hack the branding idea out of my mind but luckily in the last hour of the conference before we hopped onto the bus to go drinking I ran into a young whipper snapper who showed me how to do it. I am truly impressed and this was definitely the highlight of the conference for me.