Cite numbers or phrases from a public document by page

A public document sent here is kept in our library, to be indexed and read into cited rows; a link on a file-sharing host or carrying a signature or token is read and never kept (kept says which, and why). Each find is located on the document's own page text, exactly as typed (a number as printed: 0.10 is not 0.1, a decimal comma reads as a point; spaces optional; any case; µg read as ug), and answered with every page it is printed on (n_hits, the first 5 with their quote and cite: page, address, the document's sha256, the day read). A find not printed on the pages read is in not_found. held_as names the instruments this server reads rows from when the document is one of them. PDFs, web pages and plain text up to 40 MiB; a scan with no text layer is refused (read.no_text).