reposurgeon enables risky operations that version-control systems don't want to let you do, such as editing past comments and metadata, removing commits, splitting repositories, and joing repositories. It works with any version control system that can export and import git fast-import streams, including git and hg and bzr. Through plugins it can also handle Subversion, CVS, fossil, RCS, and darcs.
These details are provided for information only. No information here is legal advice and should not be used as such.