Legend of the Burning Sands RPG Corebook has been released at Drive-Thru-RPG. The sourcebooks covers in-depth various gaijin factions that make appearances in the L5R story like the Ashalan and Yodotai.
The corebook, while released years ago during the 3rd Edition Ruleset, is still very relevant today and a useful guide to understanding the overall story canon even if you don’t use the underlying mechanics. For those that wish to do so, there is an official conversion for mechanics in this book to use with the 4th Edition L5R Ruleset. You can find them here.
The PDF itself is very clean and crisp (much better than the old sourcebook). Bookmarks are included for those that wish to use them and provide a great navigation of the book.