To me, it just looks like a guide to what exposure per species would have in the wild and how to recreate that. But I'll read it fully later. Many believe that D3 should still be included even if UVB is used, but that's its cut down. Animals that get real sunlight might not need it at all

Rhinella marina I doubt feeds a lot on vertebrate prey, it's just very opportunistic. Now, horned frogs on the other hand do, especially C. Cornuta on other frogs. They can eat their other siblings even at the young age hence why many breeders raise them in incidual deli cups. It could meet all their needs? Many used to be raised on just fish and pink mice with no supplementation, but we do know now that this can cause other problems. There's plenty of evidence that they can do well without it.

Now, when we talk about let's say fire-bellied toads or red-eyed tree frogs, it is very obvious to me that they will use the suns rays for the vitamin D needs. Does this mean that they need it to do well in captivity? No. Would it be beneficial? Of course. But UVB is just as much guesswork. Realistically, a lot of hobbyist ain't going to pay £200 for a UV meter unless they have a large collection. UVB lamps are delicate, can be damaged or installed incorrectly. If you're using UVB, it's always better to go for a large tank, unless the species does sit indirect sunlight for hours on end (waxy monkey frogs, although this frog needs a large tank anyway) Too much or too less exposure can be bad, just as manmade D3 products. I am actually going to get one of these myself at one point. I do get the argument on UVB and I support that it could be beneficial to many species, but I not believe anyone who is keeping their frogs without UVB is providing bad husbandry... on the other hand, if the invidual species actually has been proven to benefit from exposure and it's easy enough to provide, then I would encourage the provision of UVB. But I wouldn't recommend cutting D3 from supplements.