It's the Lex Acilia Repetundarum from the second century BC; the standard reference would be CIL i.198. While parts of have been restored, there's no way that "iduibusque" could have been part of the heading, as "iduibus" simply isn't a word in Latin of any era. Nobody from Mommsen onward prints anything but "iudicibusque," because that is a word, and "iudices (d)eligere" is the usual legal phrase for picking jurymen, just like "nomen deferre" is a standard phrase for indicting someone. The author of the article did not have privileged access to some special truth about this: whatever he copied from said "iudicibusque," and he miscopied it. If you're looking for a text with notes and standardized orthography, Lindsay (1897) _Handbook of Latin Inscriptions_ 84-88.
Again, later Christian Greek texts (probably codices rather than scrolls) could have called "kephalaion" the thing Latin marked as "caput" (not in the article, but very common in Latin; Cicero uses it in _De Inventione_) or "capitulum," and in fact Greek texts did so in imitation of the Latin, but "kephalaia" is plural, and the author, despite writing about the history of terms, doesn't seem to know that.
It's also odd that he discusses Aulus Gellius' _Attic Nights_ without talking about Pliny the Elder's _Natural History,_ on which Gellius likely based his concept of an index and chapter headings. In Pliny, the chapter headings proceed logically through thematically related groups in a taxonomy, so you can drill down through the index to the chapter you want by looking for the larger genus to which it might be a species. If you're looking for a particular rock, for example, you start in the index under rocks and then look for a more specific type of rock, rather than looking under plants or geography. Gellius turns this on its head, quite possibly intentionally: none of his chapters fall into any sort of order that anyone has ever been able to discern, so you have to read the entire index of chapter headings (itself a book in length) in order to locate one you might be seeking. Besides being the first, to my knowledge, openly user-hostile interface, I think that makes it harder to believe what the author says about the Attic Nights being "only something to be consulted partially, and on occasion, rather than read and absorbed line-by-line." It's actually really hard to use the Attic Nights as a reference book in that way, not only because of how Gellius set up the index and disordered the chapters but also because it was originally published in linear-access scrolls rather than a random-access codex, making quick reference even more difficult. So, it's odd that the author skips from headings that organize a legal treatise straight to Gellius' chapter headings summarizing, but not organizing, his random miscellany without some mention in between of someone like Pliny, who organizes chapters into a taxonomy.
There's already a lot of scholarship about chapter markings and other paratextual devices in ancient literature: Butler (2009) "Cicero's Capita" in _The Roman Paratext_ shows that Cicero's speeches were capitulated in antiquity without written rubrics or headings, marking new units of text on the same argument instead by extending the first line into the left margin; surely this is a step that should have been considered on the road from legal text rubrics to chapters without headings as a temporal organizational device in novels.
Maybe the book did the topic more justice than the review.