Sonatype’s Maven integration for Eclipse (m2e) has been migrated to eclipse.org and is now available from the default update site for Indigo.

This means that you no longer have to add any Sonatype update sites as mentioned on the old (now outdated) m2eclipse site.

In particular, this also means that the old “m2e-extras” update site is obsolete for Eclipse 3.7.x and later. Things like WTP integration or Subclipse integration are now available as “m2e connectors” through Window – Preferences – Maven – Discovery.

All of this is very poorly (or not at all) documented on the new m2e home page and some people had problems with these changes.