Ground and 3.3V plane continuity are bad

[KubaO]

The ground plane and 3.3V plane have poor continuity and relatively high impedances.

I have reworked all that in https://github.com/KubaO/esp8266-pcb/tree/fixes

[besi]

Fantastic. It looks nice and tidy now on the GND plane.
Can you measure that impedance somehow or is it just looking at the traces and the plane?