It is possible to save files to a project that may not even have any specific use and which can't be used as straightforwardly as catalog images. Files of any kind can be drag'n'dropped onto the "Files" table, which makes them get saved as project files. These files will gets included in backups, when project is exported and they will also be recreated if the project is imported in the project listing view. Next to the files are Download buttons, which allows a file to be downloaded for use if required. At some point, a file preview function will also be available, which could e.g. used to see what is in the zip package. For some file types, you can already view their contents in the File preview panel (e.g. zip files, image files and text files).
If, in addition to storing files, you want to be able to share them publicly with others, you can transfer files to an (existing) CDN service, which in this case is Bunny's CDN Storage. The only effort required is to create a Storage Zone in Bunny's settings, and an apikey for it (will be entered in the user settings of the publishing application in the external services settings). There are two types of these apikeys, one read-only and one readwrite. The latter is needed for file transfer using a separately installed FTP application.
In order for files to be visible in the CDN Files table, files accessible via CDN must be located in a directory starting with "project_" followed by the id number of the project in question. The rest of the directory name can be anything. In the CDN Files table, listed on the same line as the files, are urls, which are the publicly accessible web addresses. You can use them however you like, but one should be aware that these are files distributed via the CDN service, so there is a charge for downloading them via the web and hence via Bunny.
This same CDN file storage can also be used to play audio and video files, e.g. by providing a public address referring to them in the text editing view (under the Embeddables tab, Attach embeddable and from the modal window that opens "Video file" or "Audio file"). No need to use a certain kind of directory name, but you should refer to the Bunny instructions on how to form public addresses.
In the project listing view, there is a limit of 500 MB for zip-packed files containing a backup of a project. Ones larger than that will have to be transferred using SFTP and importing need to be continue a different way (the functionality to that is available, but there is currently no visual button for it).