What does this COPY command do:
COPY dir:da9ed7f1cee89c4a2c807243af453b96796a9e873d707c519151e53ac29e79fc in /usr/local/aws-cli/
Specifically what is this dir:sha256 sum syntax about? Docker documentation does not seem to reference this in any way.
It's copying a directory from the build cache, the long hexadecimal string is a SHA256 hash that identifies directory content in the cache.