LibDOM is an implementation of the W3C DOM, written in C. It is currently in development for use with NetSurf and is intended to be suitable for use in other projects too. For further details, see the readme.
You can browse the source code via the online interface. Alternatively, you can check it out with Git:
$ git clone git://git.netsurf-browser.org/libdom.git
LibDOM is licensed under the MIT Licence.
If you would like to help develop LibDOM, or have questions about the library, please join the NetSurf developer mailing list.