code: public void postCheckout(@Nonnull Run<?,?> build, @Nonnull Launcher launcher, @Nonnull FilePath workspace, @Nonnull TaskListener listener) throws IOException, InterruptedException {
          if (build instanceof AbstractBuild && listener instanceof BuildListener) {
              postCheckout((AbstractBuild) build, launcher, workspace, (BuildListener) listener);
          }
      }
docs: Get a chance to do operations after the workspace i checked out and the changelog is written.
  @since 1.568