There is much to be learned from studying the header files and often questions arise as to where these can be found. To answer part of that question, I put together the attached pdf which is a printout of the core header files for the Arduino installation (1.8.6). It may be useful to have a copy at hand instead of wading through directories looking for a specific file.
Arduino Core Headers.pdf (1.35 MB)
It might be interesting for the reader to add the specific filenames; I might have missed it in your document though. You do give the path to the root directory.
2)
Can you add an advise for more advanced beginners on the editor / viewer to use; they might be interested in seeing it themselves. Some might try to open the files in the IDE which might not work too well 
vi/vim (Linux) and Notepad++ (Windows) come to mind.
3)
I'm more interested in the implementation than the header files
4)
Do you have a typo in your company name? pcific
PS
I use grep to find the stuff that I'm interested in.
All sounds too much like work.
If you're in Adobe Reader, the bookmarks menu is laid out according to the Windows directory structure.
Typo noted.
BTW the file name is in the top/bottom header to the right