This defense is interesting to me for a couple reasons.
Being from Canada, this is very similar to the a Wide 4-4 stack, just one less player. Essentially the WS S and Nickel and interchangeable players and are twinners between linebackers and Safeties. The ends typically play a 5 tech position and the NT and DT play whatever the play calls for, typically NT 1 tech and DT 3 tech.
Both the Will and Sam backers are usually in 30 tech positions. The front 6 are typically static and don't move much, its the DBs that move around a lot ish.
The benefit of this defense is that you will have a very very hard time running off tackle plays this way, which is the bread and butter of the run game. Where its through a counter trap or power or OZ or a simply off tackle. That's the area running plays are designed to go. Now the blocking assignments rarely include the WS safety and Nickel because they're sniffing the box and not in it, but their close enough to be able to be part of the running game. Furthermore, those same players are supposed to be really good low zones players or flats, basically they're job is don't let anything happen between the outer most player on the LOS and out of bounds and 10 yards of the LOS regardless or pass or run. Because of their position its easy to disguise them as a man2man coverage player o the inside more receive in 3x1
I don't wanna go too far into it. But its a great base and has its weakness which I wont say, but this defense can limit an offense and offensively its hard to scheme against, cause it can essentially allow your back three to play deep often while still looking like man, cover 2, or 4, without much tell based on pre-snap alignment.