KIO (KDE Input/Output) is a library in the KDE Frameworks that lets applications built on the KDE Frameworks read and write local and remote files over a wide range of protocols such as mtp (
mtp://), ssh (
fish://) and samba (
smb://). It is what makes it possible to easily open and work on remote files in text editors like KWrite and Kate, file managers like Konqueror and Dolphin and a whole range of other applications built on the KDE Frameworks.
The KIO library is modular with "slaves" for individual protocols, storage mechanisms and file archives. It supports HTTP/HTTPS, FTP, SFTP, SSH, SMB, TAR (and tar.bz2, etc) and a lot more.