Git rebase allows you to incorporate changes from one branch into another by applying each commit on the branch to the target branch. Unlike merge, it allows for a cleaner commit history by avoiding unnecessary merge commits.

One benefit of using a Git Subtree over a Submodule is that it allows you to include a single directory from a repository, making it more flexible and granular. This can be useful when you only need a specific part of another project.

Using rebase and squash in a CI/CD pipeline helps maintain a clean and linear commit history, making it easier to understand and troubleshoot changes. These features can simplify the resolution of merge conflicts and accelerate the integration of new features. Increasing the number of commits in the history can lead to a cluttered history, making it harder to identify meaningful changes.

The 'shallow clone' feature in Git allows users to clone a repository with a limited history, reducing the time and bandwidth required for cloning. Shallow clones are useful when dealing with large repositories where fetching the entire history may be unnecessary.

The company should use Separate Repositories for Code and Database. This approach provides clear separation between application code and database version control. Each repository can have its own history, branches, and releases, making it easier to manage changes independently. It also helps in maintaining a clean and focused history for each component, facilitating collaboration and version control for both application code and the database.

The correct option is git revert. Unlike git reset, which removes commits from the branch history, git revert creates a new commit that undoes the changes introduced by a specific commit. This ensures a safer and non-destructive way to undo changes. git reset, on the other hand, can be used to move the branch pointer and potentially discard commits.

A 'fast-forward' merge occurs when the target branch has no new commits since the source branch was created. In this case, Git simply moves the pointer of the target branch to the latest commit of the source branch without creating a new commit.

In large enterprises, Git's capacity to efficiently manage and process large repositories is essential. This involves handling extensive codebases, managing numerous branches, and ensuring seamless collaboration among multiple teams. A robust version control system capable of scaling with the size of the projects is crucial for maintaining a smooth workflow in such environments.

Major Git failures emphasize the importance of robust backup and recovery practices. Having reliable backups ensures that in case of failures, the repository can be restored, preventing significant data loss.

In open source projects, the Forking Workflow is commonly used. Contributors fork the main repository, create a branch for their changes, and then submit a pull request. This allows for a decentralized collaboration model.