Google has made a few changes to how channels work within Google AdSense. It is more interested with the reporting section. Note, Google AdSense added the channels feature back in 2004.
Here is the list of the changes:
• Google said it improved the user experience and given channels new, modern look.
• Since channels are primarily used for reporting, Google said it moved them into Reports alongside their other reporting features.
• Google removed the “Targeting” checkbox from custom channels, because advertisers no longer use targetable ad placement.
Google still allows you access your channels in the old channels interface for now. At some point, Google will remove the old interface.