mech spec - i'm confused!

Help and interest appreciated wrt pci mechanical specification chap 5:

1. Is the standard length the long card length in figs 5-1 and 5-2?

2. What is panel optimization?

3 is component side B the main component side ie top layer?

4.wrt figs 5-1 and 5-2,
a. is it true that fixed height 3.5v and 5v cards can only be of one of two
lengths?
b. the only difference between 5v and 3v vesions are the key location?
c. fixed height cards can only be 32 bit.

5. Why is there a need for component and trace keepout areas?

6. why is there a need to show the bracket in figs 5-1,2?

7. figs 5-3 to 5-6 show that there is no universal variable height card?

8 in fig 5-7 what is the continuous line down the centre of the page and
does the shaded region represent the contacts?

9.a in fig 5-14, is the legacy device pre 1997 pci device?
b. why is it shown the opposite way round to the pci device?
c.Does the volume define the location of any connectors?

10. Has the mech spec been a source of confusion in general?