It was a long time ago. We've been testing Sigil with Qt6 for quite a long time now.
For the record: I'm not really sold on it (export to Qt5 sigil) being a feature we need to incorporate into Sigil. I just wanted to make sure I wasn't going crazy! Those that can update to the latest Sigil--should (in my opinion). And I'm not nuts about adding a feature to the latest Sigil just to make it possible to export clips and saved searches for use with the unsupported Windows 7 versions of Sigil.
Perhaps an external tool/script to downgrade a Qt6 INI?