Which horses the term “Nedjdi” applied to?

A thought had in passing the other day: one notices a significant increase in the use by French and other European horsemen of the term “Nedjdi” (among other spellings) in the first decades of the XIXth century, to refer to some Arabian horses. I believe this increase was probably associated with the influx of Bedouin tribes, mostly ‘Anazah, from Central Arabia (Najd/Nejd/Nedjd) to Northern Arabia that was taking place around the same time. The first decades of the nineteenth century were indeed the time when the Ruwalah, under al-Dray’i ibn Sha’lan, the Fad’aan and other ‘Anazah tribes migrated to the north. In doing so, they came in contact with the Ottoman centers of Damascus and Baghdad, and with other Bedouin tribes already present in the area. People in these urban centers and Northern Arabian Bedouins alike must have referred to the new arrivals and their horses as “Nedjdi” — the ones from Nedjd. What I believe this means — and here lies the crux of my argument — is that the “Nedjdi” horses are essentially the Arabian horses of the ‘Anazah gone northwards. In the North, they would have been contrasted with Arabian horses maintained by the Northern Arabian tribes…