iCab is best known as being the little browser that could for Mac. It is considered the best web browser for Mac OS 9, being the last to maintain active updates for the operating system. iCab kept a focus on being minimalist, which enabled it to run better on slower systems, a major plus when trying to run on Classic Mac systems.
iCab however stalled in the modern generation, with 3.0.3 being very old (I believe years actually). Well, that has changed. iCab 4.0 is now out, and has been compeltely rewritten (this time in Cocoa, breaking from the old Carbon codebase).
Unlike older versions of iCab, version 4.0 is powered by WebCore, the same core that powers Safari.