The HTTP(s) protocol is supported and used for various things.  Primarily the [WebInterface] uses the port.  However, its also used for [WebDAV] and for Remote Administration with a full GUI.  HTTP(s) is also used for tunneling FTP to make it secure, and to accelerate file transfers in the [WebInterface] with the integrated [CrushTunnel|High Speed File Transfer] as part of the high speed file transfers.

For reverse proxy, if Apache is doing HTTPS and CrushFTP is doing HTTP, those protocols are "opposite".  Precede the reverse proxy path with a "!" as in the example screenshot for the reverse proxy path of "/crushftp/".  This tells CrushFTP the user's protocol is the opposite of what CrushFTP's thinks it is.