Marker to designate that this extension point doesn't operate by implementing
the callbacks but instead GitSCM has a prior knowledge about this extension.
A class which allows Git Plugin to choose a git implementation by estimating the size of a repository from a distance
without requiring a local checkout.
When GitSCM is configured to track another branch by merging it to the
current commit for every build, this Action on AbstractBuild
remembers the state of the branch that was merged.
Speculatively merge the selected commit with another branch before the build to answer the "what happens
if I were to integrate this feature branch back to the master?" question.