The default output is an ANSI colored GNU-like changelog. From a repository's root directory try:

$ vclog

To generate an a different format use -f:

$ vclog -f xml

To get a release history specify -r, --release or --history option.

$ vclog -r

Again the default format is an ANSI colored GNU-like text style.

Unlike change logs, release histories group changes by tags. The tag message is used as the release note. If the underlying SCM doesn't support tag messages than the message of the first commit prior to the tag is used.

See vclog --help for more options.