Both the CDH patched source and packages contain explicit information about Cloudera modifications. For example, in the patched source there is a top-level cloudera directory with:

• A CHANGES.cloudera.txt file that lists all the changes to the pristine source
• A patches directory that contains every patch Cloudera has applied to the pristine source. All Cloudera patches are released with an Apache 2.0 license.
• A files directory for files Cloudera created from scratch, such as man pages and configuration files. All Cloudera files are released with an Apache 2.0 license.
• A README.cloudera file explains explicitly how to recreate the patches source from the pristine source.