One of the most famous licenses is gpl, which ensures that a particular program remains free to distribute and allows its code to be examined and modified by anyone.

One of the most famous EULA licenses is GPL, which ensures that a particular program remains free to distribute and allows its code to be examined and modified by anyone. EULA stands for End User License Agreement. It is the agreement between the licensor and purchaser, where the purchaser is given right of using the software. 
GPL is the GNU General Public License.

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