This repository and the exploded build directory are from the HBase 0.20.2 source RPM above.
public HBase AMIs
bundles are official release AMIs which work with the EC2 scripts in src/contrib/ec2/ that incorporate as-released versions of Hadoop and HBase.
alt-bundles are experimental/enhanced AMIs which include things like Hadoop 0.20 patched with HDFS-630, and Ganglia 3.1 support, etc
Debian packages are available in Debian unstable. http://packages.qa.debian.org/h/hbase.html
Since hadoop and hbase are still a moving target they are deliberately not yet in Debian Squeeze.