Hello I am wondering under what license Inkscape actually is.
Most source files don't have the full GPL copyright notice which specifies the version, they only say "released under GNU GPL". This would suggest that most of the code is GPLv2+. There are also several files dual-licensed under MPL and GPL. Our Launchpad website states that Inkscape is under GPLv2.
However, I encountered a file which is GPLv3 only, apparently copied from GIMP (src/util/expression-evaluator.cpp). If we really are GPLv2, then including this file is not legal, as GPLv2 is not compatible with GPLv3. We would need to change our license to GPLv3 or GPLv3+ to include this file, or contact the original authors for a GPLv2 or BSD license.
PS: our Windows devlibs also seem to be in a "gray area", because most of the copyright information is not present, which might break the license terms of the libraries. I'll try to remediate this by adding the license files from each package, once I have some spare time (i.e. not very soon).
Regards, Krzysztof