What is light portals and how to add it in Daz Studio

in The Commons
What is light portals and how to add it in Daz Studio?
I cane across this term when viewing the old thread about lighting.
Thanks.
Comments
Which old thread?
https://www.daz3d.com/forums/discussion/205481/how-to-properly-light-an-interior-scene-with-characters-in-it
The second post in this thread provides the steps for enabling them https://www.daz3d.com/forums/discussion/265391/lighting-an-indoor-scene-with-only-outdoor-light-iray
As far as I am aware Light Portals, and the Architectural sampler, are no longer present - they've been deprecated even if they are still there.
Light portals were sometimes used with Reality/Luxrender but interior lighting with current Iray has other options.