Maybe I'm missing something obvious, but is there documentation on the SEDE schema anywhere? As listed here http://odata.stackexchange.com/stackoverflow/query/new, it's not obvious what all the fields are. I've had a root around, but can't find anything.
The most up-to-date schema reference can be found here:
I've got that question favourited on Meta and I use it constantly.
Note: the content in that question is sourced from the documentation included with the data dump download.