ref: 7fa5db9d6a8d3b7d1430cab7df9fda9b8ee1ec0b
dir: /sys/src/cmd/ext4srv/NOTES/
Based on https://github.com/gkostka/lwext4 None of the sources are GPL-licensed: * xattr handling removed altogether * extents logic replaced with a BSD-3 licensed one found in https://github.com/ngkaho1234/lwext