Yes, you are allowed to modify and distribute open source software under the GPL license. The GPL (General Public License) is a type of open source license that allows users to freely modify, distribute, and use the software for any purpose. This means that you can modify the code of the software and distribute it for free on the internet.
However, there are some conditions that you must follow when distributing the modified software. These conditions include:
1. You must also distribute the source code of the modified software along with the executable version.
2. You must include a copy of the GPL license with the distributed software.
3. You must make it clear that the distributed software is under the GPL license and that users have the right to modify and distribute it further.
Open source software, in general, refers to any software that is freely available for use, modification, and distribution. The GPL license is just one type of open source license, and there are many others with different terms and conditions. It is important to check the specific license of the software you are using to ensure that you are following all the necessary guidelines for modification and distribution.
In summary, yes, you can modify and distribute open source software under the GPL license, as long as you follow the conditions stated in the license. It is also important to be aware of any other open source licenses that may apply to the software you are using.