A question on sXBL and XBL 2.0

I just saw on W3C Web site that Web appformats WG has released a Last 
Call Working Draft for XBL 2.0, and I have some questions about the WG 
strategy about XBL 2.0 / sXBL relationship.

- will the sXBL working draft be dropped in favor of the more general 
XBL 2.0 (there is a specific chapter on XBL 2.0 with SVG, and it seems, 
by looking at the table of contents, that the xSBL TOC is a subset of 
XBL 2. TOC too) ?
- is sXBL a subset of XBL 2.0, or is there some (volontary) subtle 
differences between the two recomandations ?

Thanks,

Herve Girod