It should be noted that the Guild descriptions comes from 1st Edition WFRP Stone and Steel, but it's probably the most in depth individual level look at Dwarfs from a non army perspective, so people take a lot of the lore from it, and aspects of it are still picked up by modern day sources, if modified so that stuff like Dwarf Necromancy isn't ported over. Even Boney picks up some stuff from Stone and Steel occasionally (most of what is available of Gazul is from the book, and so is the Order of the Stone Wall which has been mentioned at least twice in quest).
2E does not expand on those books, but 4E goes back and explains it again. A reminder that as it's 4th Edition, it's pick and choose rather than DL canon:
"The elder is responsible for maintaining the clan's Book of Grudges (Dammaz Kron), removing grudges where settled, and adding new entries whenever a new grudge is forged. The elder also keeps a number of other tomes in their possession. One is the Book of Remembrance (Zagaz Kron) which records the deeds and acts of renown by clan ancestors as well as living clan members. Updating the Book of Debt (Skuld Kron) which details the debts of the clan and erases those that have been settled also falls to the elder. Lastly, the elder maintains the Book of Ancestors (Gromthi Kron) which delineates the ancestral line of the clan to the present generation." Page 51 Archives of the Empire 4E
As can be seen, Boney already uses a different word for the Book of Debt in the form of the Dalaz Kron, which has been mentioned by Belegar in the K8P Sword Ceremony. Also, it should be noted that that paragraph is mentioning Imperial Dwarves, which is why a single Elder is in charge of updating all four books. A more established Hold Dwarf clan likely has dedicated Runescribes and Loremasters instead of just an Elder to do it.