OT: Should this be documented? I only recently discovered that espasyncwebserver doing some = new ... ; if (some) is not the same thing as basic malloc on current Core; Not used updated toolchain very much because of platformio shipping the old one for so long
Might also be surprising for Arduino in general:

• AVR Fix operator new arduino/Arduino#108 is ongoing
  https://github.com/arduino/ArduinoCore-avr/blob/master/cores/arduino/new.cpp
• SAMD https://github.com/arduino/ArduinoCore-samd/blob/master/cores/arduino/new.cpp uses the same override

It is useless when exceptions are disabled in the toolchain.
But we have them as an option.

edit: our new is std c++'s one, not a malloc wrapper

Yes, but my main question is about the null check routines. It does not trigger exception, but board reset still happens when internal malloc fails in low memory situations.

async web server being the case where there are flow objects are constructed with new and checked for NULL afterwards. which spectacularly fails with 4KB-large context:sys stack trace