Contributing to Eclipse Tycho: How to get rid of "Plugin execution not covered by lifecycle configuration" errors in workspace?

[hd42]

When I set up a new eclipse following https://github.com/eclipse/tycho/blob/master/CONTRIBUTING.md#using-the-eclipse-installer-oomph to look at the tycho source, I get 17 "Plugin execution not covered by lifecycle configuration" errors in the workspace.

Is the documentation outdated and I have missed a step? (Probably outdated, as for example, I only get a "Tycho" working set, not as described also a "Tycho-Extras" set)
Or is the oomph setup incomplete? Should it include some lifecycle mappings?
Or should the lifecycle mappings be excluded in the POMs, as the goals are handle by PDE?