The customize playground popover includes an option to run the nightly version of WordPress.

The action https://github.com/WordPress/wordpress-playground/actions/workflows/refresh-wordpress-nightly.yml pulls down the nightly each day and commits it to the repo and deploys (the action is currently failing but that's the idea at least). An example commit can be seen at 6be65fb

As the zip file is replaced each time, it has the effect of making the repo rather large.

Since #1705 and #1721 it's possible to run playground from trunk with a download from the WordPress/WordPress repository.

I propose the action for updating the nighly be removed and the dropdown be replaced with run trunk.