GPL, or GNU General Public License, is a “copyleft” license that an open source author might attach to their open source software. It comes with a number of permissions and restrictions, including: Permission to modify the work, as well as to copy and redistribute the work or any derivative version. Permission for inclusion in commercial products Inability to impose further restrictions on the rights granted by the GPL Programs distributed as pre-compiled binaries must be accompanied by a copy of the source code, a written offer to distribute the source code via the same mechanism as the pre-compiled binary, or the written offer to obtain the source code that the user got when they received the pre-compiled binary under the GPL. For more information on open source software licenses and their requirements, refer to License to Code: How to Mitigate Open Source License Risks.