The convenience rollup -- officially known as Windows 7 SP1 convenience rollup -- isn't Service Pack 2 for Windows 7, but it's the next best thing.
The new Windows 7 convenience rollup is cumulative back to Service Pack 1, which Microsoft released in 2011. It doesn't include updates to IE 11 (which are released separately) or updates to .NET releases. But it does include core Windows fixes, security fixes and hot fixes.
In January this year, I asked Microsoft officials about plans to deliver this convenience rollup -- something execs announced a year ago. Officials said Microsoft's update strategy was all about Windows as a Service, a k a Windows 10, moving forward.