The ".part2.rar" suffix indicates this is not a standalone installer. You must have all related parts (e.g., part1, part2, etc.) in the same folder to extract the full update.
Individual armor pieces that can be mixed and matched for different protection levels. Blade.and.Sorcery.Update.v11.2.part2.rar
While U11 was the primary content drop, the focused on stability, bug fixes, and minor adjustments to the new systems introduced in the initial U11 release. the focused on stability