Added more detail including the class that sets the default variables
for exclusion and the list of actual variables that are excluded by
default.
(From yocto-docs rev: 7764a54add2911c2da8174e48e4d3166a873d63a)
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
b298bb586e