A reader coming to the Parts of the Earth from modern occult literature will find a great deal attributed to them: elemental natures, tarot correspondences, sephirotic placements, ranks of authority, detailed characters and specific magical offices. Almost none of that is in Dee.
Dee's table gives four things per Part. The name. The Aethyr it falls under. The Zodiacal King that governs it. The number of ministers dwelling in it. It also relates each Part to a region of the earth. That is the whole of the primary record.
The additions came in two main waves. The first was the Hermetic Order of the Golden Dawn, which from the 1880s absorbed Dee's Enochian material into a much larger synthesis and supplied it with the correspondences the order used everywhere else: elements, tarot trumps, Hebrew letters, positions on the Tree of Life. Samuel Liddell MacGregor Mathers took the basics of Dee's system and fitted them into a ritual structure Dee would not have recognised. The second wave was Aleister Crowley, who learned Enochian in the Golden Dawn and carried its assumptions into his own work, adding a Thelemic layer on top.
There is also a reading dispute at the root of the thing. Nalvage's words describe ninety-one Princes and Spiritual Governors, which supports treating each name as a being to be addressed. But some careful readers of Dee's own tables, notably Benjamin Rowe, have argued that the name in that column is the name of the Part in the angelic language rather than of any resident spirit, and that the word Governor properly belongs to the twelve Zodiacal Kings listed in a separate column. Both readings can be defended from the manuscript. Practice has overwhelmingly followed the first, largely because the Golden Dawn did.