The extension UUE refers to files that are encoded using the Unix-to-Unix method. With this method, binary data, eg programs or pictures can be transmitted by means of an ASCII-coded text. Thus, data can be transmitted via e-mail, even if the programs do not support transmission of binary data.
Today, UUE is largely superseded by the more flexible MIME, as MIME is better supported and easier to handle. Uue encoded files are still widely used in Usenet.
Some packagers can open and decode UUE encoded files.