Ahh! Thank you, EnTerr--
That is exactly the information I needed.
I found -- now that I knew what to look for -- that an edit page is available from Developer Home > Manage My Channels > [select channel] > from "Channel Details" pull down to "Descriptions" >...
That page is not the same as the edit page given by your direct URL, but changing one seems to affect the other, so I'll assume that they're functionally equivalent.
Thanks again for your help.
--Gil
--Gil