One report -- I guess you could call it a report -- that I think would be useful would be an interactive map of the ebook that laid out in various orders the contents of the files and allowed the user to take action on one or more pieces and get 'the big picture'
chapter_01.html (repeat for each file)
Tags used: <p>, <h1>, ...
Images used:
img001.jpg,
img002.jpg, ...
Classes used:
chap,
chap1, .....
IDs used: FILEPOS0001, FILEPOS002, ...
Images
img0001.jpg:
front.html,
chap2.html, ...
img0002.jpg:
img0003.jpg:
chap2.html,
chap2.html,
chap31.html,
foot.html
ID
#top used (12):
front.html,
chap12.html, ...
#top_1 used (0):
#filepos0011 used (3):
front.html,
chap2.html, ...
Links
Table01
Chap4.html,
Chap7.html, ....
Classes
......
Fonts
.....
Other Files (not sure about this one )
.....
Clicking the Class 'chap1' takes you to the style sheet for that class appropriate to that file.
Clicking the second Chap2 in image3 takes you to that position in chap2.html, while clicking the image3 link opens image2.jpg
Left click a link takes opens the file and/or takes you to the right position, BUT a right click brings up a context menu to [Rename], [[Replace], [Delete], [Delete All]...
So since #top_1 is not used I could right click and delete it
Same for image2
#filepos0011 is supposed to be #endnote11 so I could do a [Replace All] right from the 'map'