from the cover:
A guide to the island of Duin, part of the great city of Marienburg
Published for WimCon 2014
from the Foreword:
This booklet contributes to the setting by developing the Kislev enclave in Marienburg. You will find interesting locations and NPCs, and a few good hooks for your scenarios. It was written for WimCon 2014.
Klein Kislev is definitely set in the city of Marienburg. So you should see this book as an appendix to other source material of that city. Characters listed here have links to the rest of the city and the text mentions characters and locations in Marienburg that are detailed in other source material
Next to that, Klein Kislev clearly has roots to its larger brother. I tried to emulate that as well, using the sourcebooks for WFRP1, Something Rotten in Kislev, and for WFRP2, Realm of the Ice Queen. It allowed me to add some quite foreign characters and stuff to the city.