Description
Helps you figure out when and why a commit was merged into a branch.
If you use standard Git workflows, then you create a feature branch for each feature that you are working on. When the feature is complete, you merge it into your master branch. You might even have sub-feature branches that are merged into a feature branch before the latter is merged.
In such a workflow, the first-parent history of master consists mainly of merges of feature branches into the mainline. git when-merged can be used to ask, "When (and why) was commit C merged into the current branch?"