From the PDF introduction
Cityscape presents a variety of new feats, spells, and warlock invocations that were developed in an urban environment or that you can use in a city-based setting. While these are the most prevalent of new tools and tricks for the urban adventurer, however, they are far from the only ones. For those who do not practice such esoteric arts, not only magic items, but also alchemical and entirely mundane tools, exist to enhance the abilities of the city explorer.
Several of the abilities and items herein reference mechanics from Cityscape .