A WebmasterWorld thread reports that Google has dropped a search command that used to show a site's pages that were included in the supplemental index.
The command that worked was site:www.seroundtable.com **** -asssdsd but that seems to no longer be working.
The last time I tested it was when I wrote at Search Engine Land, Is Google Gearing Up To Drop The Supplemental Result Label? I guess they were gearing up to drop the supplemental results command and possibly the supplemental results label is next to go.
This is not the first time Google dropped the ability for us to locate the supplemental results of our pages in the Google index. The very old supplemental results check stop working sometime after September 2006.
As Tamar reported earlier this week, Matt Cutts of Google is taking suggestions on what should be the next feature for Google Webmaster Central Tools? One of those items on the poll is a way to list supplemental result pages within the tool.
So maybe Google will drop it from the index and allow SEOs and Webmasters find this information in Webmaster Central?
Forum discussion at WebmasterWorld.