pdk/ contains the locked PDK setup helpers and managed PDK checkouts.
smoke/syn/ contains Yosys synthesis and source-export integration.
smoke/sta/ contains OpenSTA constraints and timing integration.
sdf/, when supplied by an implementation flow, contains post-layout netlist and SDF collateral consumed by post-layout simulation.

The local Makefile is reserved for implementation flows that require the selected PDK, technology collateral, and often site-specific tools.

Generated layout, report, and database outputs must remain outside tracked source paths. Treat PDK-dependent physical-design results as toolchain-specific evidence and record the selected profile, PDK, and validation command when handing off a change. See Engineering Workflow.