# request a preview site > Make selections below for the most common configuration options, then use the > _start pull request_ form to be redirected to GitHub. > A large number of other configuration options are _possible_, but are not yet fully described.

customize GitHub checkout

All of the repositories below will be checked out at the current main branch as a baseline. Check one or more repos to provide use a differnt branch, PR, or tag, or provide one or more PRs to merge with it, and/or customize the merge strategy and options to work around merge conflicts.
repo baseline merge with merge strategy merge options
GitHub repository to check out and build
starting point GitHub reference
optional space-delimted list of references to merge into the baseline
merge strategy
additional space-delimeted -X options to pass to git merge
https://github.com/ipython/traitlets/
https://github.com/ipython/comm/
https://github.com/jupyterlab/lumino/
https://github.com/jupyter-server/jupyter_server_terminals/
https://github.com/jupyter/jupyter_core/
https://github.com/jupyter/jupyter_events/
https://github.com/ipython/ipython/
https://github.com/jupyterlab/jupyterlab_pygments/
https://github.com/jupyter/jupyter_client/
https://github.com/jupyter/nbformat/
https://github.com/jupyter/nbconvert/
https://github.com/ipython/ipykernel/
https://github.com/jupyter/nbclient/
https://github.com/jupyter-server/jupyter_server/
https://github.com/jupyter/notebook_shim/
https://github.com/jupyterlab/jupyterlab_server/
https://github.com/jupyter-lsp/jupyterlab-lsp/
https://github.com/jupyterlab/jupyterlab/
https://github.com/jupyter/notebook/
https://github.com/jupyter-widgets/ipywidgets/
https://github.com/jupyterlite/jupyterlite/
https://github.com/jupyterlite/pyodide-kernel/
customize JupyterLite
If given, an optional gist will be cloned to provide the content of the JupyterLite site. If the gist contains jupyter_lite_config.json and/or jupyter-lite.json, this will be merged into the generated configuration of jupyter lite build and the runtime application.
start pull request