> BiwaScheme https://www.biwascheme.org/ is a simple browser-side
> interpreter.  It doesn't pre-transpile (you write Scheme directly in the
> script tag)

Seems that the forward.scm framework is implemented on top of Biwa! The
source code of its homepage <https://hyperdev.fr/defunct-forward.scm/>
contains a <script> tag with Scheme code as you say.

Amirouche's other project <http://scheme-lang.com/cons/> apparently uses
Chibi Scheme compiled in the way John mentioned, judging by the page's
source code.