By default Okular saves reviews in PDF files without writing to file but with some kind of dark KDE magic. I have tried to Google how to write reviews into PDF file (because I wanted to send reviewed PDF to my colleague) and found that I should use "Export as -> Document archive" feature. I've exported my reviewed file and got a file with ".okular" extension which can be opened only by Okular, so this document is not as portable as PDF. With the 'file' command we have figured out that this file is a ZIP-archive containing the PDF file and two XML files. The PDF file contains all the reviews inside and the XML files does not contain any information useful for reading reviews (just some links to PDF and themselves). So, the question is as follows: If Okular CAN write reviews into a PDF file, why not to provide an easier way to get the file with reviews which can be opened in other PDF viewer (without need to extract a ZIP archive)? It's a quite common usecase of reviewing to write a review inside a PDF file and send it to somebody who can edit this document? Reproducible: Always
I'll quote the manual ************* Since Okular 0.15 you can also save annotations directly into PDF files. This feature is only available if Okular has been built with version 0.20 or later of Poppler rendering library. You can use File → Save As... to save the copy of PDF file with annotations. ************* And the rest of the other things you ask for there's various bug about it already.
Seems like I tried "Save Copy As..." which does not save annotations. Sorry.