Check out https://code.google.com/p/npoi/source/browse/ -- bridged from SVN to GitHub at https://github.com/svn2github/npoi
You can find the XSSF and XWPF under the ooxml directory. The codeplex branch seems to be behind these two.
You can find the XSSF and XWPF under the ooxml directory. The codeplex branch seems to be behind these two.