Curious what you mean by learning? Learning about TLPs? Learning about FPGA DMA Engines like XDMA? Learning about PCIe switches / retimers? Learning about `lspci`?
Nothing specific! I learned how to implement USB(-C) because there was some specific hardware I wanted to create. I could see the same thing happening with PCIe in future. With USB its longevity was fairly obvious to me, with PCIe I’m not well informed. Thanks for giving me some acronyms to explore!