Quality

• Every request for c/{id}.js counts as a page load on the owner's plan. Never load your own script again from JS.
• Your code ships exactly as saved; nothing minifies it. Keep it small.
• Fetch once per page, shared by every mount: const data = (window.__sbFetch ||= {})[url] ||= fetchAll(url);
• Headings in the mount start at h2 or h3, fitting the section they sit in.
• A countdown or ticking clock gets a text label and no aria-live; announcing every second drowns a screen reader. Changing content (filter results) can use aria-live="polite".
• Images from the owner's content use its alt text; decorative ones get alt="".