Here are some quick insights until OP does his blog post.

For a high-level breakdown of the files changed:

https://public-001.gitsense.com/insights/github/repos?p=focu...

681 files were changed, with the most being C/C Header files.

The file age is interesting as it shows 175 files were changed over a 2 year period. And you have about 279 files that were probably just imported and never touched again or were infrequently changed. Note renaming files/directory can skew this number.

And if you are looking for a heatmap, you can look at

https://public-001.gitsense.com/insights/github/repos?p=comm...

The superscript value <number>v besides the file/directory indicates how many versions there are. So the higher the version, the greater the focus. In this case, the kernel, include and fs directories saw most of the activity.

In the future, I will gray out files that no longer exists on the latest tree, but for now you can look at the year beside the files/directories to get an idea of when they were last touched.

And here are the top 20 most frequently changed files

           path          | revs
   -----------------------+------
    kernel/system.c       |  151
    kernel/proc.c         |  128
    include/sys/syscall.h |  124
    kernel/exception.c    |  120
    include/kernel/proc.h |   95
    Makefile              |   90
    kernel/main.c         |   80
    user/shell.c          |   69
    fs/inode.c            |   67
    winix/sys_stdio.c     |   60
    README.md             |   53
    driver/tty.c          |   52
    kernel/sched.c        |   49
    kernel/clock.c        |   46
    winix/wini_ipc.c      |   45
    fs/fs.h               |   44
    winix/mm.c            |   44
    fs/makefs.c           |   42
    winix/sigsend.c       |   42
    init/init.c           |   41

Disclaimer: I'm the creator of the tool for the links above and there is a bug where the menu will say 45 days window but it is a 5 years window.