If there are no redirects for the default site, but there are redirects for multi-sites, the "Edit List" button is missing from the toolbar of the URL Aliasing Redirects screen (see screenshot below). Normally, the button is next to the "Add Redirect" button.
This issue will be fixed in a currently undetermined software update. Until it is released, you may implement the following workaround.
1) In the site dropdown, select "Default" as the site.
2) Choose "Add Redirect" and provide innocuous redirects that no one could accidentally use. The "Edit List" button should now appear.
3) Change the dropdown to your multisite. The "Edit List" button is now available.