Apple’s Safari browser is now available in public beta on Windows. A little spelunking shows that it uses Windows Installer packages and that they’re built with WiX. Sadly, they didn’t use WixUI.
On a more serious-but-sad note, the packages have ICE validation errors (other than the typical ones), contain VBScript custom actions, and the main Safari package uses a custom action to install the Apple Software Updater package (instead of using a chainer). Already there’s a forum report of a 2738 error with the VBScript CA. And I guess the only way to report bugs is via forum posts…? It’s not clear. The “Report Bugs to Apple” command on the Help menu seems focused on rendering problems. Too bad. After all, Setup Development Is Just Development.