It is not an html tag, its a Cascading Style Sheet property.
page-break-after: ?
when printed, breaks the page at the location of the tag (always, auto: default)
page-break-before: ?
when printed, breaks the page before the location of the tag (always, auto: default)
so you would do something like this:
<style>
br { page-break-after: always; }
</style>
then whenever you use the <br> tag, it would insert a page break after the tag