You can use the comps.xml file, also known as the groups file, to find which environment includes a particular package.
For example, choose your favourite mirror and go to the file
and use your browser find function to search for the package name.
The file has a structure like this:
group (only groups or packages can be used in kickstarts)
packagereq : type = mandatory | conditional requires = | default | optional
environment (not used in kickstarts, for anaconda only?)
grouplist (groups making up the environment)
optionlist (groups that are optional for the environment plus uservisible groups)