Zip files can be uploaded within your Assets as well as within a Project.
Key points regarding zip files, when used in a project, are:
ZIP file type is not supported in review mode.
When uploaded to a project either as an Approval Asset or a Reference File, you will not be able to review or generate reports.
ZIP files can be downloaded.
No thumbnail is generated.
Key points regarding zip files, when uploaded into the asset library, are:
ZIP file type is not supported in preview mode.
ZIP files can be added to an existing collection and added to a new collection.
ZIP files can be downloaded.
ZIP files can contain attributes.
ZIP files are able to be shared via the Get Download Link feature.
ZIP will appear as the asset thumbnail.