For starters, it's typoed.
Code:
/home/eschwartz/git/Sigil/src/main.cpp:549:39: error: ‘class QWebEngineProfile’ has no member named ‘setURLRequestInterceptor’; did you mean ‘setUrlRequestInterceptor’?
549 | QWebEngineProfile::defaultProfile()->setURLRequestInterceptor(urlint);
| ^~~~~~~~~~~~~~~~~~~~~~~~
| setUrlRequestInterceptor