It would be nice to have FME Flow have file extension restrictions as to what types of files can be uploaded to the resource folders. The ability to restrict types of extensions, especially executable, would be a major safety addition to Flow.
If this could be added by user/groups level, that would allow the sys admins to restrict or allow file types based on their groups. For example, some users only allowed to upload CSV files, others more privileged users can upload spatial datasets, others can upload anything except executable. This also will have the benefit of keeping the resources clean and not be a dumping ground for less experienced users not knowing what the intended purpose of that resource is.