Triggering the Magic Sysrq from a SuperMicro HTML5 console:

* Bring up the virtual keyboard and press Alt (it is sticky)
* Select from the top menu: Macro -> Macro -> PrntScrn
* Press F to pay respects, eiter on virtual keyboard or physical

F can be repeated as long as the Alt key on the virtual keyboard is active/depressed.

https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html