Thanks for the insightful documentation.
OTH, I feel the new "Citation" section seems to be relatively heavy compared to the other sections.
Just like the "Markdown syntax" section, we can let readers find comprehensive introduction in the Pandoc's manual.

In particular, wouldn't it be better to explain mainly about pandoc-citeproc?
This is because this is the only way to support variety of output formats including PDF.

Just re-read my text. Based on my experience trying to explain this stuff to novices I continue to feel that essentially all of this information is required to sort out the precise relations between pandoc-citeproc, bibtex and biblatex. Still, if you want to rewrite my text, fine.

Nonetheless, the current version of https://bookdown.org/yihui/bookdown/citations.html is still both factually inaccurate and needlessly disparaging (“pandoc-citeproc … may not render certain bibliography items correctly”), and incomplete (it does not even mention biblatex). These issues, at the very least, should be fixed as a matter of urgency.