Sigurður Atlason, the manager of The Museum of Icelandic Sorcery and Witchcraft, quickly summarized his best answer in an interview in 2014 that "they do not exist outside legends and the museum walls".^[1]

The replica (or reconstruction) you refer to is located in his museum and was created by artist Árni Páll Jóhannsson specifically for the museum.^[1] Dr. Guðrún D. Whitehead, assistant professor of Museum Studies at the University of Iceland, wrote a short article on these sinister pants where she says:

"The popularity of and debates about the necropants ... [have] been a favourite of mine for years; an interest fuelled by the many academic debates it opens up: authenticity, the value of replicas, the visual representation of oral heritage and history, dark tourism and the grotesque in museum."^[1]

---

Out of interest, I did a search in the Icelandic digital library for all instances and mentions of nábrók in newspapers and periodicals of the Faroe Islands, Greenland and Iceland.

I searched for nábrók, Finnabrækur, nábuxur, skollabrók and papeyjarbuxur (all of which refer to the same thing). Of course these results are narrow and anecdotal, but what I found was that there was not a single instance where they were discussed outside a context of "Here's a fun myth..." or directly referred to as folklore. The first example I found was from 1891.

The legend of nábrók originates from Jón Árnason's epic collection Icelandic Folktales and Legends which appeared in two volumes in 1862-1864. Unfortunately it is not fully available in English but Jacqueline Simpson has translated a selection of stories from the collection, first published in 1972, revised and reprinted a few times since then.