The open-source license type that encourages software sharing and redistribution is known as the GNU General Public License (GPL). This license allows users to freely use, modify, and distribute software while ensuring that all derivative works remain open and accessible under the same terms. By promoting collaboration and transparency in software development, the GPL fosters a community-driven approach that enhances innovation and encourages developers to contribute to larger projects. This type of license is foundational in the open-source movement.