A paint sealant is a synthetic polymer (close to a synthetic wax but wth MUCH HIGHER strength) which can be applied to the paint and it protects the paint underneath from swirls scratches etc. There are permenant paint selaants and there are temporary ones. There is only one widely used permenant paint sealant which might be called a "replacement" for a clear coat that is opti-coat paint sealant. Though you cant use that as a replacement but it is very very tough. It is applied over the clear coat and doesnt let anything penetrate and can only be removed by applying a high abrasive compound. But they are pretty difficult to apply, unless one has done it before
The Wolfgang Deep Gloss Paint Sealant is a temporary sealant, with a life ranging from 2-5 months depending on surface prep and condition kept in. Price is 5500