diff --git a/src/gui/org.kde.ksudoku.appdata.xml b/src/gui/org.kde.ksudoku.appdata.xml
--- a/src/gui/org.kde.ksudoku.appdata.xml
+++ b/src/gui/org.kde.ksudoku.appdata.xml
@@ -7,6 +7,7 @@
 <component type="desktop">
   <id>org.kde.ksudoku.desktop</id>
   <metadata_license>CC0-1.0</metadata_license>
+  <project_license>GPL-2.0-only</project_license>
   <name>KSudoku</name>
   <name xml:lang="ca">KSudoku</name>
   <name xml:lang="ca-valencia">KSudoku</name>