Yeah, that had me bamboozled. Tried to find a way but concluded that there isn't a way to view historic Script Shield logs. Well, I'm only able to click the Shield log link which shows the current activity log, but nothing going on at present.
there's no log but there's a
report file for the script shield. Problem is that it can't be tweaked like for other shields as there's no settings for the scriptshield in the UI. This may be reached from an ini file probably but I haven't checked yet.
So what you got is just a report file located here:
C:\ProgramData\AVAST Software\Avast\report
with not much inside except that the module runs and scans got started. If you could change the report settings which I think is somehow possible, you'd have the details of scanned files.