/usr/src/linux-headers-4.15.0-1013-azure/sound is in linux-headers-4.15.0-1013-azure 4.15.0-1013.13~16.04.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/src/linux-headers-4.15.0-1013-azure/../linux-azure-headers-4.15.0-1013/sound