Backup "Download in browser", "Single archive file", aborted, location of temporary tar, gz files

Hello:

Can anyone help with this? I attempted a domain backup with the options:
“Backup virtual servers”, “Download in browser”, “Single archive file”, in Virtualmin.

Due to another bug or limitation in virtualmin, the download was only at a moderate 450Kb/s or so, this is
documented elsewhere, however I did not know about that limit when I started the backup.

My issue is the domain backup was about 20Gb. The server…not underpowered by any means…took a while to write the tar or tar.gz file, then the download started.
Because of the speed limit I had to abort the download. Thankfully the abort option in Webmin worked and server resource usage was back to normal.

The download was started as a 17 Gb tar.gz file.

I have unsuccessfully searched,as root for any large tar, tar.gz files, find / -name *.tar, etc.
I found this in /tmp/.webmin:

-rw-r–r-- 1 root root 44 Jun 14 16:13 668358_31882_4_backup.cgi

But it is a small file, with only these text contents:
/domains
./virtualmin-backup
./backup.lock

I need to know the flow of the backup, download to browser option. I think, but am not certain, there are some large files somewhere, which I would like to delete.
Or does the abort option delete these?

Thanks for your help.