This looks like a major thing that could help us big time.
It actually makes no sense whatsoever if not for a very small number of people that actually want to know the extents a file actually occupies on a mass storage device, and BTW we already have tools (namely getfileextents and myfragmenter) that can do (most of) that work, JFYI:
The attempted revamp of the extents project is about creating:
1) a command line version <- which will be used only by a subset of the already small target audience
2) a new tool capable of managing "corner" cases, such as UUID volume addresses, $MFT entry embedded files, etc., i.e. those things that currently available tools miss or manage in a not fully correct way.
The whole thing only re-started because Steve6375 posted what is almost a chocolate covered banana (again JFYI), i.e. a "wrong" question in the above linked to thread:
that issue is already (I believe) solved by the re-compiling by erwan.l, both as win32 and win64 bit, of the original getfilextents, so it has in itself a very low priority or actual usefulness in practice.
 which is pretty much unusual for Steve, maybe, like everyone else, he is getting older ...