Arduino / ESP32 compile memory usage message

[sparky2019]

Hello - I am compiling an app for a ESP32 in Arduino IDE and when it completes it reports the memory usage of the ESP32 eg :

"Sketch uses 761130 bytes (58%) of program storage space. Maximum is 1310720 bytes.
Global variables use 41440 bytes (12%) of dynamic memory, leaving 286240 bytes for local variables. Maximum is 327680 bytes."

Question : what size memory is it basing the 1310720 bytes on (4M, 8M or 16M)

Thanks in advance.

CS