This image shows Mune+Lumen=Ferrox for 289 tokens “As a by product”. I don’t know where it comes from. https://wd.neon-wonderland.com/dragon/eggCombos/6 shows that breed as 824 tokens (expensive). Since they have at least 35 fragments, the breed must cost at least 20*35=700 tokens, so the image is wrong.
The only way of costing less than 700 would be if one could use a discounted breed. E.g. both parents platinum for 6 tokens per fragment, for at least 6*35=210 fragments. The only gold with 35 fragments are Ferrox, Lumen, Basileus, and I can’t find a case with both plat parents.
Is there any way of getting gold research eggs for less than 700 tokens (i.e. neon is incorrect)?