This is a print head, the back side of the contact plate.
IC is not connected to the nozzles (except for Vin and GND).
Each of the unrecognized leg IC has a contact on the contact plate.
Since the introduction of memory to the print head, it's always been microwire.
Preceded had memory TC9WMC2
(256 Bytes, 16-bit, 3.3V, 4 functional pins: serial clock, select, data in, data out).
TC9WMC2 is easy to read and write.
I suspect the new 3-wire memory is microwire with internally joined "serial in" and "serial out" through 10k resistor.
Here is a evolution of EEPROM memory connection to CPU:
Luke