x86_64 uses /sccache (host dir bind-mounted into the job container by the runner config); aarch64 on the klokka host uses a runner-owned dir. Both persist across releases via RUSTC_WRAPPER=sccache. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01GLUwWE2KmFPzhKaf67tWbx