opkg config files

[Simon Matthews]

Can someone please explain to me, or point me to some documentation on
the format of the opkg config files.

>From what i can make out
/etc/opkg/arch.conf
points to the different feeds, the details of which are stored in the
files all-feed.conf, armv4t-feed.conf ...
What is the number besides the feed name?
What is the format of the xxx-feed.conf files

Thanks
Simon