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See: https://github.com/DSpace/DSpace/wiki
Git adoption by the DSpace developers
Final Note: The DSpace developers (committers), are currently firmly committed to using SVN for official contributions to the DSpace source code. The cost of migrating to Git is still substantial, especially as many modules are not being mirrored on Github, not all developers are fluent in Git, and our release process is only configured for subversion.
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