A small recipe for the pages you need
Assemble a local PDF page recipe
Select local PDFs. Processing stays in this browser; export downloads a separate file without changing sources.
For ordinary unencrypted PDFs. Do not rely on preservation of signatures, forms, bookmarks or other document-level features.
Example: A:5-3,A:1,A:1 copies pages 5, 4, 3, 1, 1. Repeated pages are intentional.