JNVME 0 and 1

This look like the X12SPM-LN4F, so this FAQ should apply :

https://www.supermicro.org.cn/support/faqs/faq.cfm?faq=34848

JNVME0/1 are PCIe 4.0 x8 Slimline SAS Connectors. These two Slimline SAS connectors located on the motherboard to support two PCIe 4.0 x4 NVMe connections. This connector provides high-speed and low-latency connections directly from the CPU to NVMe Solid State (SSD) drives. Cables available from SMCI eStore: https://store.supermicro.com/catalogsearch/result/?q=slimline sas