Why the pinout on the Raspberry Pi Pico development board, are labeled under the board?
It’s a good design question.
Rookie designer maybe.
The only thing one could move alot is the button, but I guess they wanted it close to the USB port.
Notice how far away L is from Data+- and the trace width for low impedance. That’s important.
Look how close the DCDC converter is to the input. That too is important not to share ground noise.
They could have gone to under-sized font for the print screen of epoxy paint but risk smearing or gaps.
I would have gone for thinner Data tracks (lower L/C) with thin guard grounds on either side to make room for screened pin labels. Then the dielectric gap might have to decrease to raise C and match the increased L to maintain L/C ratio, which compromises stiffness. It’s possible with fine line coplanar capacitance to raise C but not as much as gap to parallel bottom side gnd.
So an extra mm or more to fit the screen print is possible for both sides and the logo is definitely oversized.
What would you do differently and maintain CMRR and trace impedance?
Also a lot of users longish mismatched cable impedances with ringing: and with 25 Ohm driver impedance, they could put shorted pads for 603 series resistors to match the high cable impedances and reduce ringing with a cut and place 220 to 300 Ohm R.