The speaker presented a prototype called City Visualization, which visualizes the NPM dependency ecosystem of a project using a city metaphor. The buildings represent the NPM dependencies, and the quarters represent the dependency levels. The visualization uses web technologies like A-frame and metrics like height, area, color, times installed, and times appeared to represent the data. The goal of the tool is to merge all the information retrieved from the packages and show it in a city-like format. The speaker also mentioned that the City Visualization can be used in virtual reality using MetaQuest 2 glasses.