https://www.blackhat.com/docs/eu-14/materials/eu-14-Chen-WebKit-Everywhere-Secure-Or-Not.PDF
- the unnamed branch (version) of a file tree under revision control
- the base of a project on which development progresses.
- always contains the latest cutting-edge version of the project
- the most unstable version
- Other terms for trunk include baseline, mainline, and master
- toolchain for Windows https://webkit.org/webkit-on-windows/#installing-developer-tools