The open-source code release was announced by Jonathan Tang, of the search features team, on the Google Open Source Blog.
According to Tang, “Gumbo seeks to provide a simple library that can serve as a basic building block for linters, refactoring tools, templating languages, page analysis, and other small programs that need to manipulate HTML. It’s written in pure C for ease of interfacing with other languages, and has no outside dependencies.” More details can be found on the Gumbo project page.