This site is a static rendering of the Trac instance that was used by R7RS-WG1 for its work on R7RS-small (PDF), which was ratified in 2013. For more information, see Home.
IMO, the whole notion of "exceptions" is not really introduced; there seems to be the assumption that this is already known. IMO, an introductory, high-level overview might be nice here. --Denis Washington