Most Inkscape source code is available under the GNU General Public License, version 2 or later.
Notable exceptions are:
- some libraries in src/3rdparty and src/2geom (mostly GNU Lesser General Public License or Mozilla Public License).
- a few files copied from GIMP, which are available under GNU (L)GPL version 3 or later.
- a few files which are dual-licensed, which means that they offer the additional permission to alternatively use them under another license.
As such, the complete binaries of Inkscape are currently covered by the terms of GNU GPL version 3 or later.
License of individual source files
The license of each individual inkscape source file can be found in the first few lines after "SPDX-License-Identifier:". The license text of every such license can be found in LICENSES/. Some files are dual-licensed, e.g. "GPL-2.0-or-later OR MPL-1.1", which means you can choose one of these licenses.
Libraries have their COPYING or LICENSE file in the respective subdirectory.
See also https://spdx.org/licenses/ for the full license texts, and https://spdx.org/ids for the standardized header format.
Suggested reading for license version compatibility: https://www.gnu.org/licenses/gpl-faq.html#AllCompatibility
Roughly summarized (I am not a lawyer, this is not legal advice):
- You may legally make the following license changes without having to ask anyone:
LGPL-2.1-or-later -> GPL-2.0-or-later -> GPL-3.0-or-later
LGPL-3.0-or-later -> GPL-3.0-or-later
- Due to that, the resulting inkscape must be under GPL-3.0-or-later.
- Any license that is not "-or-later" is evil and must not be used in the inkscape project.