forgive me the question. Which NSX version are you referring??
I tried with GET /api/4.0/firewall/globalroot-0/config and even whit GET /api/4.0/firewall/globalroot-0/config/layer3sections/1005/ (as you can see on picture bellow, where 1005 is the section id o layer3) but, I don't get your result "default.".
More reference can be found here.
I'm talking about NSX-T.
Help will be appreciated