This section is one of the traditional primary divisions of the Degé Kangyur, despite only containing a single text which is not, strictly speaking, Buddha-word, being a treatise. The Lithang, Degé, and Urga Kangyurs include this text, which in most other cases is found only in the Tengyur.
The text in question is the Vimalaprabhā (dri med ’od), a commentary on the Laghutantra of the Kālacakra said to have been written by King Puṇḍarīka, eighth king of Shambhala and son of King Yaśas (who compiled the Laghutantra itself, Toh 362). It was first translated into Tibetan from Sanskrit in the 11th century by the Kashmiri scholar Somanātha and Sherab Trak, and later revised by Zhangtön Dodé Pal, Tsultrim Dar, and Shongtön.
The dkar chags explains that “although it belongs with the treatises, as it is the sovereign of all the tantra commentaries that unravel the most definitive, secret, highest of all mantra systems, it has been published here—just as past scholars have placed it—in order to honor it as the equivalent of the Teacher’s own word.”
The division is placed by the compilers of the Tōhoku catalogue between the Old Tantras and the Incantations, and although it appears to be intended to come right at the end of the Degé Kangyur, as its final fifth chapter shares a volume with the Kangyur dkar chags (catalogue), we have placed it here along with the other Tantra sections for convenience and to maintain the sequence of Toh numbers.
It is also reproduced in the Non-Dual Tantra section of the Tengyur (Toh 1347).
The commentary is divided into five main chapters corresponding to the chapters of the Laghutantra itself:
1. The Extensive Commentary on the World System Chapter
2. The Extensive Commentary on the Inner Chapter
3. The Extensive Commentary on the Sādhana Chapter
4. The Extensive Commentary on the Empowerment Chapter
5. The Extensive Commentary on the Gnosis Chapter.