This Counter32 is a free-running, cumulative tally of PCIe unsupported request errors recorded against this PCIe endpoint's receive path since the counter was last reset by a reboot or reseat; concretely, the device received a PCIe transaction (e.g. an access to an unimplemented register or capability) that it does not support. Because it never wraps back to zero on its own, an admin uses it as the lifetime baseline against which the 15-minute/hourly/daily/weekly gauges on this same row are compared to spot fresh activity. A blade that shipped with this counter at 0 and now reads 187 has accumulated 187 such faults since it was last powered up, which on a healthy riser should stay at 0.