well /etc/yum.repos.d is a path to a bunch of files which contain the information on each of your repositories. even though livna is designed for fedora, yellow dog is based off of fedora so they work.
if your looking to edit your repositories try using gedit or your favorite editor to edit the files:
# gedit /etc/yum.repos.d/extras.repo
this will edit your extras repository. each repository has their own file. so livna will have livna.repo etc.