Why .local/share ?

[Orion White]

Hi--

I've begun to use the XDG base directory standard for my projects, and I 
am very happy with it.

However, I do not understand the rational behind .local/share. I have 
searched the Internet for some explanation, but to no avail.

Why is .local/share not just .local/ or .share/? Why the two levels? And 
what is supposed to go in .local/ other than share/?

Thanks,
Orion White