...I just tried - using CorePure64 9.0
When I plug an sd card in, it is automatically detected and automatically shows up in the mount tool as mmcblk0p1.
$ dmesg
...
mmc0: new high speed SDHC card at address aaaa
mmcblk0: mmc0:aaaa SS04G 3.69 GiB (ro)
mmcblk0: p1