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You can repeat step four for different pull requests in the same repository if you want to test them simultaneously. If you are really happy with the result, you can create a branch to keep a reference to the result of the applied changes:

$ git checkout -b 11.0-custom

Using a different branch will help you remember that you are not using the version from GitHub, but a custom one.

The git branch command can be used to list all the local branches you have in your repository.

From then on, if you need to apply the latest revision of the 11.0 branch from GitHub, you will need to pull them without using --ff-only:

$ git pull origin 11.0