The short explanation
VESA defines the display modes computers use. The names are abbreviations rather than resolutions: QFHD is 3840 x 2160, WQUXGA is 3840 x 2400, QUXGA and WQSXGA are other high-resolution variants. Anything within the available bandwidth can in principle be carried.
Where you run into it
PC modes behave differently from television modes in a chain. A device happy with 4K60 may not pass an unusual monitor timing, and a television may refuse a mode a monitor accepts without complaint.
Whether the mode is offered at all depends on the capability data and the preferred timing in it — which is why a graphics card sometimes shows a shorter list of resolutions than the display can actually handle.
How the DR HDMI 8K handles it
The DR HDMI 8K supports all VESA video modes within its 1500MHz bandwidth, including WQSXGA, QUXGA, QFHD, WQUXGA and 4K/8K. Keeping the display's preferred DTD timing in the advertised EDID, for example by copying the sink EDID, is what stops a PC from falling back to a generic mode.
Want to test your own HDMI chain?
The DR HDMI 8K is sold through the HDFury.eu web shop.