- The freedom to run the program, for any purpose.
- The freedom to study how the program works, and change it so it does your computing as you wish.
- The freedom to redistribute copies so you can help your neighbor.
- The freedom to distribute copies of your modified versions, giving the community a chance to benefit from your changes.
There is a lot more to the GPL than the four freedoms listed above however, the license details can be difficult to read and decipher. Richard Best, a qualified lawyer in New Zealand, England, and Wales, has published a human readable summary of the GPL license.
Inspired by how Creative Commons offers a human readable version of its licenses, the summary explains the core concepts of the GPL and outlines the position in relation to copying, distribution, fees, modifications/derivative works, distributing non-source forms, termination, and downstream licensing.
It’s important to note that the document is not endorsed by the Free Software Foundation nor a substitute for the full license text.
I encourage everyone participating in the WordPress ecosystem to read the full license text at least once. However, the summary does a good job explaining the core components of the GPL without having to dig into the license.
If you have questions concerning the GPL, I suggest seeking legal council with a lawyer familiar with software licensing.