This is a simple permissive license, created by the FSF. It is Free and GPL compatible. The FSF recommends it for "small supporting files, short manuals (under 300 lines long) and rough documentation (README files, INSTALL files, etc.)". A copy of this license was taken from https://www.gnu.org/prep/maintain/html_node/License-Notices-for-Other-Files.html on 2018-03-05.
Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without any warranty.