/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/ is in linux-source-4.4.0 4.4.0-51.72.
This file is owned by root:root, with mode 0o755.
..
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/abiname
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/amd64/
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/amd64/generic
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/amd64/generic.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/amd64/generic.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/amd64/lowlatency
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/amd64/lowlatency.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/amd64/lowlatency.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/arm64/
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/arm64/generic
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/arm64/generic.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/arm64/generic.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/armhf/
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/armhf/generic
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/armhf/generic-lpae
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/armhf/generic-lpae.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/armhf/generic-lpae.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/armhf/generic.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/armhf/generic.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/fwinfo
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/i386/
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/i386/generic
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/i386/generic.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/i386/generic.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/i386/lowlatency
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/i386/lowlatency.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/i386/lowlatency.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc-e500mc
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc-e500mc.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc-e500mc.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc-smp
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc-smp.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc-smp.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc64-emb
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc64-emb.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc64-emb.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc64-smp
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc64-smp.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/powerpc/powerpc64-smp.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/ppc64el/
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/ppc64el/generic
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/ppc64el/generic.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/ppc64el/generic.modules
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/s390x/
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/s390x/generic
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/s390x/generic.compiler
/usr/src/linux-source-4.4.0/debian.master/abi/4.4.0-50.71/s390x/generic.modules