Technically, an FZZ file is a (similar to a .zip file). It acts as a container that bundles all the necessary assets of a project into a single, portable package. Inside an FZZ file, one will typically find:
How to Open and View FZZ Files: The Ultimate Guide to FZZ Viewers
: This is the core XML-based document containing the netlists, copper layers, solder paths, component placements, and custom notes.
To understand how an FZZ viewer operates, it is necessary to look at what happens under the hood of an .fzz file.
The primary purpose of an FZZ file is to save disk space. However, decompression takes CPU power. A premium FZZ Viewer uses multi-threaded decompression to ensure you aren't waiting minutes for a file to render.
: There is no official or widely supported online viewer for .fzz files. However, some developers have created experimental Fritzing to SVG converters