...
These are extensions for the m2e plugin and are available through the m2e marketplace (accessible from within Eclipse).
SCM Connectors
These are CVS, Subclipse, Subversive, EGit, etc SCM extensions for m2e.
m2e-scm
m2e-cvs
m2e-subclipse
m2e-subversive
Embedded Maven 3 (optional)
...