I have good news.

1) My prototype comparator finally works under Linux Chrome and
Chromium, see https://scheme-live.github.io/ff.scm/ It was only tested
on Ubuntu 19.04. (the problem what with chrome, not Chibi)

2) I tried Gambit JavaScript backend, it works very well, See
https://scheme-live.github.io/scheme-fuss/todomvc/ That said, it does
not support R7RS as of yet. I am waiting 12th or 13th October Gambit
30 meeting [0] to decide whether I will continue with Chibi or Gambit.

[0] https://mailman.iro.umontreal.ca/pipermail/gambit-list/2019-September/009152.html

3) I want to change the format used in implementation metadata
repository [1] to rely on chunks that is n-tuple or lists of n items
where n is fixed. I am thinking about using n=4. This could help (me)
demonstrate SRFI-168 capabilities. What do you think? Triples or Quads
are the defacto standard for representing data (e.g. wikidata,
dbpedia). I think it will help to rely on a similar formalism.

[1] https://github.com/schemedoc/implementation-metadata/

Let me know what you think!