Particular signals for Core-3588j SoM

IBlaZerG

Hello everyone!
I am going to make a custom motherboard with this SoM Core-3588J,
and I found than the description of some signals at Specifcation is not so clear for me.
They are:
30 PWRON_L PWRON_L RK806-1 POWER EN, Active L 5V
32 VDC_EXT VDC_EXT RK806-1 VDC IN(DC IN Auto Power ON 3~5V
34 PMIC_EXT_EN_OUT PMIC_EXT_EN_OUT PMIC_EXT_EN_OUTPUT, Active H 5V
36 VCCA_RK806 VCC_5V_S PMIC Power supply of PLDO6 and system 5V

As for signal 30 PWRON_L PWRON_L RK806-1 POWER EN, Active L 5V , I understand more or less ok that this signal is used for POWER ON the SOM module, except that the signal into 5 volt domain, but the rest is a little bit enigma for me.

I was wondering if anybody could explain the meaning of each signal for me, include the power domain of 5 volts.
Thans a lot.