[BioC] The usage of ls("package:hgu95av2.db") shown in AnnotationDbi.pdf

[Peng Yu]

Hi,

in AnnotationDbi.pdf, it gives the following example code. I don't
quite understand the second command. Does it mean that 'hgu95av2.db'
is in the namespace of package? What does ":" mean?

library("hgu95av2.db")
ls("package:hgu95av2.db")

Regards,
Peng