DMD is our tool for improving Firefox’s memory reporting. It helps identify where new memory reporters need to be added in order to reduce the “heap-unclassified” value in about:memory.

DMD has always worked well on Linux, and moderately well on Mac (it is crashy for some people). And it works on Android and B2G. But it has never worked on Windows.

So I’m happy to report that DMD now does work on Windows, thanks to the excellent efforts of Catalin Iacob. If you’re on Windows and you’ve been seeing high “heap-unclassified” values, and you’re able to build Firefox yourself, please give DMD a try.