As far as I know the two most popular licenses are MIT: "The above copyright notice and this permission notice shall be included in all copies or substantial p

As far as I know the two most popular licenses are MIT: "The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software" And GPL: You may convey verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice;