Simple definition
Extended file attributes store additional metadata, including security labels or application-specific information, on Linux filesystems.
Purpose and use
Extended attributes, or xattrs, attach additional metadata to files for applications and system policies.
How does it work?
They use namespaces whose access rules and meaning depend on the operating system and filesystem.
Example and verification
During copying or restoration, verify that required attributes have been preserved.
Points to watch
Copying file contents does not guarantee preservation of security attributes or other metadata.
In short
A file may retain identical bytes while losing metadata needed for its intended use.