The reasons why shielding holes need to be drilled around this line on the PCB are as follows:
1. These holes can act as electromagnetic shielding to prevent electromagnetic signals in the circuit board from interfering with other circuits. They can also prevent electromagnetic interference from other circuits.
2. These holes can increase the heat dissipation area on the circuit board and help dissipate heat.
3. These holes can be used as vias to connect different layers of the circuit board, making the circuit board more stable.