I don't know.
I would say the problem is that opportunity is long gone. No time and motivation on my side.
All information is public. From the get go it was clear to me that the usability and practical side of the proposal and how the feature should be used was considered secondary (or not say all) to the desire to have a complex and impractical solution based on xml.
Quote: "I'm not so excited about adding the formatting capability, at least not this way. I think that it could be a very useful thing to allow for specially-formatted output from GNU make. For example, perhaps an output format in XML that could be easily sucked into tools like Eclipse or whatever for further parsing (I'm not a huge fan of XML but it is relatively universal). Now that we have the output sync capability it would be straightforward to combine these and format the output of recipes for proper XML encoding as well."
That sole idea made it clear to me the use case was not understood and I tried to explain why the xml output was only a good option only on paper, but lacked in the usability aspect (your regular developer working on optimizing a gnu make based build framework will not care about using xml parsers, but prefer a very tight change-build-test cycle, so using awk or shell ours the best option here) .
I received 0 feedback after the reply quoted above, even after reworking the patches to go in the directions suggested without sacrificing the feature entirely.
TBH, I was very disappointed by this attitude and know that it is possible to run projects in a minute constructive manner, and also know there are better make flavours or there which allow better debugging and make the developer life easier instead of painful.