From the Introduction:
Welcome to the first installment of Unearthed Arcana, a monthly workshop where D&D R&D shows off a variety of new and interesting pieces of RPG design for use at your gaming table. You can think of the material presented in this series as similar to the first wave of the fifth edition playtest. These game mechanics are in draft form, usable in your campaign but not fully tempered by playtests and design iterations. They are highly volatile and might be unstable; if you use them, be ready to rule on any issues that come up. They’re written in pencil, not ink.
The material presented in Unearthed Arcana will range from mechanics that we expect one day to publish in a supplement to house rules from our home campaigns that we want to share, from core system options such as mass combat to setting-specific material such as the Eberron update included in this article. Once it's out there, you can expect us to check in with you to see how it's working out and what we can do to improve it.
Eberron Update. This month's installment is relatively straightforward. We're rolling out some rules to help you convert your Eberron campaign to fifth edition. The Eberron campaign setting was created by Keith Baker and first published for D&D in 2004. It combines pulp adventure and intrigue in a world where magic-driven technology has produced airships, trains, and similar advancements comparable to early 20th-century Europe. The continent of Khorvaire, the center of Eberron's focus, has recently emerged from the Last War, a terrible conflict that saw the kingdom of Cyre transformed into a lifeless gray wasteland called the Mournland. That catastrophe shocked the remaining kingdoms into an uneasy peace that has held so far.
Full details on the Eberron setting are available in several PDF products available through dndclassics.com. This article focuses on mechanical conversions for several of the key elements unique to Eberron.