, we are looking at a specific milestone in the evolution of modern software development tools. This particular file represents the final version of the Qt 5 series
Refined Maturity: Most bugs present in early Qt 5 releases were ironed out by this version.
If you're still hunting for the standalone qt-opensource-windows-x86-5.15.2.exe, you're not alone. It’s effectively the "last of its kind"—the final version where the offline installer wasn't restricted to commercial accounts. Qt 5.15 licensing update - Qt Forum
Once installed, you need to configure the IDE (Qt Creator) to find the kit.
Use Cases for Qt Open Source Windows x86 5.15.2.exe