Datasette fixes unnecessary preloading issue for Firefox

Summary

Simon Willison noticed that Firefox was wasting both client bandwidth and server processing cycles by silently preloading the next tab page, so he added a patch to Datasette to stop sending `link: rel=next` HTTP headers to Firefox.

Why it matters

This exposes a 24-year-old Firefox behavior that turns a standard HTML pagination hint into an unwanted network request, silently taxing servers and users. The applied fix is a specific user-agent workaround rather than a standards-level correction, highlighting how long-standing browser quirks can silently degrade web performance at scale.

Highlights

• Following an open bug report, Firefox has been using the `link: rel=next` header as a preload trigger for approximately 24 years.
• The solution is a browser-specific suppression: Datasette simply skips the header for Firefox requests.
• Willison notes that this feature was written in 2002 and its existence had been completely forgotten.

Critical take

This 'solution' essentially uses user-agent detection to bypass behavior that could otherwise be standards-compliant. This implies that other browsers with similar preloading logic will encounter the same issue. A more robust solution would have been to tie the header to an explicit consent mechanism or to use a non-standard rel value.