I shipped four HTML pages that convert email archives to PDF. Their addresses were /eml-to-pdf , /msg-to-pdf , /mbox-to-pdf and /pst-to-pdf . They are ordinary Next.js pages. They return text/html . They are not PDF files.

Sixteen days after launch, according to the commit that moved them, Google still listed every one as "URL is unknown to Google". Bing, which had crawled the rest of the site and indexed 32 pages there, had held /eml-to-pdf at "Discovered but not crawled" since the launch date. The same commit records that the responses, including for Googlebot and bingbot, matched pages those engines did crawl. I did not re-open Search Console or Bing Webmaster myself.

The one trait they shared

Other pages on the site were being crawled in the usual way. These four were not.…