Comment by dfrage

People who follow his blog will be familiar with at least some of the following:

http://www.catb.org/~esr/software.html

Some distance down the list is reposurgeon, which has been used to convert Gnu Emacs and many smaller/younger repositories to git, and is in the process of converting GCC: http://esr.ibiblio.org/?tag=reposurgeon

Not directly software: http://www.catb.org/~esr/projects.html