Not sure exactly what you mean, but Firefox allows you to specify both new tab and new window behavior, even independently. Firefox Default, Custom page or just blank.
All I have for New Tabs is 'Firefox Home (Default)' and 'Blank Page', it does not allow me to set a Custom URL.
Which is why I have an extension installed to do it.
I'm not too bothered by this, otherwise I would likely set it to HN and waste even more time than I already do.