I've just published draft #5 of SRFI 143.  It was submitted
by John Cowan, author of the SRFI.

<https://srfi.schemers.org/srfi-143/>

Here are John's comments on this draft:

  This is the last call version of SRFI 143, including two
  implementations (R6RS and not) and test suites for
  Chicken, Chibi, and R6RS.  There is some
  implementation-specific support for Chibi and Gauche.

Here's the diff:

<https://github.com/scheme-requests-for-implementation/srfi-143/compare/ae5d725887ec4dc43ed3bbb622988edef3803f73...2630700e83d99855548ff7b84bdd755ddddebac5>

Regards,

SRFI Editor