BSD许可证
FreeBSD is released under a variety of open-source licenses. The kernel code and most newly-created code are released under the two-clause BSD license which allows everyone to use and redistribute FreeBSD as they wish. This license was approved by Free Software Foundation and Open Source Initiative as a Free Software and Open Source license respectively. Free Software Foundation described this license as "a lax, permissive non-copyleft free software license, compatible with the GNU GPL". There are parts released under three- and four-clause BSD licenses, as well as the Beerware license. Some device drivers include a binary blob, such as the Atheros HAL of FreeBSD versions before 7.2. Some of the code contributed by other projects is licensed under GPL, LGPL, CDDL and ISC. All the code licensed under GPL and CDDL is clearly separated from the code under liberal licenses, to make it easy for users such as embedded device manufacturers to use only permissive free software licenses. ClangBSD aims to replace some GPL dependencies in the FreeBSD base system by replacing the GNU compiler collection with the BSD-licensed LLVM/Clang compiler. ClangBSD became self-hosting on 16 April 2010.