I know that list, but understand it a different way. Isn't it a list on which platforms i can install Qt itself
and which compiler i can use to build applications? It doesn't tell me, on which platforms i can install my
builded application, or am i wrong? I can't see Windows 8.1 or Windows 10?

From that side:
"Qt is supported on a variety of 32-bit and 64-bit platforms, and can be built on each platform with GCC,
a vendor-supplied compiler, or a third party compiler as indicated in the table below."

For me it tells me on which platforms i can built Qt from it's source with GCC.

*confused*