content: https://www.haiku-os.org/about/faq/#what-license-is-haiku-released-under https://www.gnu.org/licenses/license-list.en.html#GPLCompatibleLicenses  They consider it the X11 license on here. It falls under the umbrella of "GPL-Compatible Free Software Licenses. The following licenses qualify as free software licenses, and are compatible with the GNU GPL."