How can I find My Channel list on a Mac computer
It's not clear what you're asking, but you can get an XML listing of installed channels by browsing to http://<roku ip>:8060/query/apps (e.g., http://192.168.0.120:8060/query/apps).
It's pretty clear what they're asking for: a list of their installed channels on the Roku website viewed on their computer.
Surely there's a better way to view the channels one has installed than some obscure API query?!