diff --git a/demux/demux_mkv.c b/demux/demux_mkv.c
index abea342ed2..8fd4f42798 100644
--- a/demux/demux_mkv.c
+++ b/demux/demux_mkv.c
@@ -18,6 +18,8 @@
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Parts under HAVE_GPL are licensed under GNU General Public License.
  */
 
 #include <stdlib.h>