refers to a proposed (but ultimately unreleased in its original form) revision of the global standard for surface-mount PCB footprint design. While many designers search for a "7351C PDF," the official IPC standard currently remains at the
version, with the intended "C" updates largely absorbed into the newer IPC-7352 Guideline Overview of IPC-7351C ipc-7351c pdf
: Moved from strictly rectangular component "courtyards" (the keep-out area) to contour-based courtyards that follow the actual shape of the component to save board space. Local Fiducials refers to a proposed (but ultimately unreleased in