Temporary files usage in explain

I have a query that creates a large number of temporary files, in this example ~ 45GB.

Looking at the query plan I can't figure out where temporary files are being generated.

Explain plan: https://explain.depesz.com/s/BXGT

Usually I'm looking for "external merge Disk" to see temp files usage but, in this case, the only reference to that is 299,368kB in the last but one node of explain.

Can anyone help me understand where the 45GB are in that explain?

Thanks,

Matteo