A site's templates/ is parsed after the embedded set, so the last definition of a
name wins and a theme redefines one block while inheriting the document
(ADR-0019). Per kind exactly two files are overlaid — base.html and that kind's
block — because overlaying every site template into every set lets a listing's
"main" leak into bundle pages, which is the collision per-kind sets exist to
prevent. Both directions are tested.
templates/theme.css in the site root replaces the reference stylesheet outright;
there is no merging to reason about. static/ is served verbatim under /static/,
through the same os.Root-backed fs.FS, and directory paths answer 404 so it never
indexes its own contents.
Queue entries 6 and 7 are deferred again with triggers: the cascade's consumers are
stage toggles, view selection and cache flags — none of which exist — and declared
types are read by ordering, feeds and check, none of which have landed. Building
either now is the speculation that justified withdrawing them.
Evidence: a real site override renders <section class="mine"> inside the embedded
document with canonical intact, the listing still uses the embedded block, and
/static/site.css and /static/img/logo.svg are 200 while /static/ and /static/img/
are 404.