Each runtime contains its own file state. This is how Nextjournal guarantees reproducibility across environments. This is true across all languages: Python, Clojure, Julia, R, and Bash.
If a researcher wants to update a language (i.e. Python, Clojure, Julia, R) file system, they may do so by creating a Bash cell within that runtime.
To run a bash cell in another language:
Insert > Code Cell: Bash > ... > Change Runtime > [select other environment]