It seems that qt5-webkit depends on libwoff2dec.so.1.0.2 if woff2 is installed.
This should be recorded as a genuine dependency or the build modified to explicitly exclude woff2.
A commit references this bug:
Date: Fri Jul 5 20:30:55 UTC 2019
New revision: 505935
www/qt5-webkit: enable woff  support
- woff support was automatically enabled if installed,
- but not in clean environments, fix that.
Reported by: Martin Birgmeier <d8zNeCFG@aon.at>
Thank you Tobias