Bundling these files into a ZIP archive makes them easier to transfer over the internet and reduces the storage space they occupy. Security and Safety Warnings
There are no widely known general-purpose programs that open these files. Opening them typically requires the original software that created them or a Hex editor for manual data inspection. Working with Zipped e7v Files
Some versions are used by electronic structure software to store data on 3-dimensional grids.
Downloading unknown file types, especially in compressed formats, carries inherent risks.