The Server Message Block protocol, better known as SMB, is one of the most popular ways to transfer files over a network. It has been built into Windows for over 20 years (and the open-source Samba implementation is frequently used on other OSes), but version 1.0 has largely fallen out of use thanks to several major security vulnerabilities. Microsoft deprecated SMBv1 in 2014, and Windows 10 no longer includes it.
Solid Explorer adds support for SMBv2 file sharing protocol was written by the awesome team at Android Police.