MeowBit Pin 19?

I was going through the meowbit uf2 bootloader’s github and i found this line " CFG_PIN_P19, PC_8, // hack to expose sdio-d0" I am way in over my head, but when i check that pin for high and low pulses Makecode can detect an sd card being inserted or removed sometimes.

there should be 40 pins cus the meow bit is compatible with microbits 40 pin glodfinger so you show try it and if you using arcade use the microbit program with the meowbit extenstion