Numbering is complete only after the downloaded PDF has been inspected. Keep the exact source, range and settings together until the result is accepted.
Verify first, middle and last labels
Compare source and result side by side. Confirm page count and order, untouched neighbors, label text, position, contrast and absence of clipping. Exercise every form, link, annotation, bookmark, accessibility feature or signature you rely on.
A new PDF needs an independent check
PDFNumber draws visible text and serializes a separate file. It does not promise byte identity or preservation of every document feature. Keep the untouched source, open the download in another trusted viewer and inspect every numbered page, overlap, contrast, form, link, annotation, accessibility relationship and signature before relying on it. Compare the first, a middle and the final selected page, plus one untouched neighbor on each side when available. Confirm the page count and order, reopen the saved file rather than the browser preview, and test the viewer or printing workflow that will actually receive it.