APITrace was introduced in April of last year as a way to help graphics driver developers debug the graphics stack. This free software program allows for easy OpenGL API tracing regardless of driver. APITrace 2.0 was then introduced in September to support the latest OpenGL 4.2 specification and to provide other new functionality. Today the program has reached the version 3.0 milestone.
APITrace 3.0 provides a new top-level "apitrace" command, trace and re-trace support for new APIs, and the ability to trim traces. There's also many bug-fixes. APITrace does have a useful GUI, but now the new apitrace command is meant to simplify using the program for tracing and re-traces from the command-line. The new APIs being supported for traces and playing back traces is EGL, OpenGL ES 1.0, and OpenGL ES 2.0. Trimming traces is useful for debugging driver issues by being able to trim a trace specifically to the faulty API calls, rather than needing to store the entire trace, which could be gigabytes in size.
The APITrace 3.0 release announcement was made on the Mesa development list.