ISC license
The ISC license is a permissive free software license written by the Internet Software Consortium (ISC). It is functionally equivalent to the simplified BSD and MIT/Expat licenses, with language that was deemed unnecessary due to the Berne convention removed.
Initially used for ISC's own software releases, it has since become the preferred license of OpenBSD (starting June 2003), among other projects.
History
Before accepting the license as a free software license, the Free Software Foundation asked for clarification of the text. In July 2007, as a result, "and distribute" was changed to "and/or distribute".
The Free Software Foundation eventually approved the ISC license as a lax, permissive free software license, compatible with the GNU GPL.As of March 2015, The OpenBSD template still uses the original "and distribute" phrasing.
Text
A template of this license is:
Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.