Q:

using new BigQuery UI to link to an external project

This page shows how to use the classic BigQuery UI to link to an external project.  Can this be done with the new UI?
EDIT: To be more explicit, the new UI has a "pinning a project" functionality which seems to allow the user only to choose from their own list of projects, whereas the "classic" UI allows the user to Switch to Project > Display Project and then enter any project name, not just one that they have a membership role in.

A:

There are some limitations for the new BQ UI listed here.
And one mentions what you asked:
Also note that the BigQuery public datasets are not displayed by default in the BigQuery web UI. To open the public datasets, enter the following URL in your browser.

https://console.cloud.google.com/bigquery?p=bigquery-public-data&page=project

Once you've opened the project, pin it.

