Google SEO
Best practices — web.dev
What should a PWA app shell provide for SEO?
A progressive web app should make critical indexable information available in its initial rendering rather than relying exclusively on a service worker to display it.
Further analysis
Use this entry as an audit checkpoint. The cited source establishes the context; the direct answer identifies what to check before choosing an action.
In SFT, this topic relates to Structure. Check whether the signal is visible on the page, connected to the rest of the website and supported by understandable evidence.
Related search terms include PWA SEO, app shell. Use them to describe the issue in a brief, audit or answer page.
Applying SFT
Structure turns a rule into readable architecture: headings, URLs, structured data, visible content and clear hierarchy.