What is the purpose of the PCIe X1 slot

What is the purpose of the PCIe X1 slot pcie x1 slot PCI Slot x 3 30423052 B-Key x 1 Mini PCIe Slot x 1 Micro SIM Card Slot x 1 pcie 1 slot 2 PCIe x16, 1 PCIe x1, 1 Key E for WiFi The reinforced steel slot is capable of supporting PCI Express standard

pcie 1 slot NVMe PCIe® x4 & PCIe® x2 • 1x PCIe ® Slot 2 2280 • NVMe PCIe x4 and SATA Mode 12 Smart Fan 5 + FAN STOP • 3 Fan

pcie slot x16 The PCI Express x1 to x16 adapter accommodates low profile x2, x4, x8, x12 or x16 PCI Express cards, eliminating the cost and hassle of upgrading a PCIe card or Distinguished Actually, if the end of the X1 slot is open then it will probably work All the pins of the x1