Interesting. They are the update files. Searching files by date/time shows 3 copies each of maybe 20 files totaling 3 X 180 MB = 540 MB were downloaded to the Opera update directory at the same time this morning, but only 1 copy of each reside in the directory now.
There was an update today to -329, it appears that the necessary files were downloaded 3 times!
I will continue to monitor this. I did terminate the download stream at some point today but it was at several hundred MB - way more than the apparent 180 MB for an update.
I am surprised that an Opera update is 180 MB now.