checkdmarc 6.0.1 on Python PyPI

SPF: the RFC 6652 reporting modifiers ra=, rp=, and rr=, added in 5.8.0 and removed later, are recognized again; their values are validated against RFC 6652 §3 (rp= per erratum 6579) and surfaced in the parsed result as ra, rp, and rr next to exp, and a malformed value is warned about and ignored instead of failing the record. Warnings also cover the two RFC 6652 §3 semantic rules — rp= and rr= do nothing without ra=, and ra= is ignored in a record reached through an include — and exp= and these modifiers are now honored after all in any order