The Introduction to Zope code is kept in a public CVS repository at http://cvs.zope.org . Anyone can check out a copy of the latest development code from here. To commit code, you must sign [[Introduction to Zope] Corporation]'s committer's agreement and put your code under the ZopePublicLicense?.
See http://dev.zope.org/CVS for more instructions.
Note: Transition to ZopeSvn is ongoing.
See also CodeRepositories.