sybsensitivity?

http://manuals.sybase.com:80/onlinebooks/group-cnarc/cng1110e/dblib/@ebt-link;pt=12272?target=%25N%15_12482_START_RESTART_N%25

If someone could explain to me what SYBBOUNDARY and SYBSENSITIVITY are,
I'd be much obliged.  

I modified tds_willconvert() to support SYBIMAGE last night (minor change)
and came across these again.  The function returns the correct value for
them now -- we don't convert them to or from anything, even to themselves
-- but I couldn't find anything in Sybase's references that explain what
they are.  The closest I got was in the DB-Library manual, 

	SYBBOUNDARY
	Security sensitivity_boundary type.
	Use DBCHAR as the type for program variables.

	SYBSENSITIVITY
	Security sensitivity type.
	Use DBCHAR as the type for program variables.

	For more information on server datatypes, see 
	the Transact-SQL Reference Manual.

AFAICT, though, the T-SQL manual is mute on the subject.  

Many thanks. 

--jkl