I think you’re a bit confused abut what kind of file Writer creates. Its native format is not plain text. A document is represented as a sophisticated XML structured description. Formatting, including breaks, are encoded by XML tags with all necessary information to lay out the text (which is only a small amount of the total description for the final result) in a page, be it a sheet of paper or a screen.
You then understand easily that a page break is not simply a U+000C FORM FEED, but a more complex object giving also directives about what happens with the break (such as change of page geometry = page style, page numbering restart and other actions.
Even CR LF are not recorded in the internal representation because they have no meaning in the ODF semantics. Only a paragraph break is significant. Paragraph contents may span several lines and line boundaries are dynamic because they depend on paper size, indents, font size and weight, … Therefore a line break may occur anywhere and these break positions (within paragraph text) vary according to typographical attributes.
Internally, Writer does not use FF, CR or LF.
Apparently, you want to use Writer as a text editor (to create **plain text = UTF-8 files). Writer is not intended for this. As @mikekaganski mentioned, a plain text file undergoes one conversion on open to translate it into internal format with internal semantics, if possible (then there are approximations) and again on save to translate to external format. In your assumed case (plain text file creation), all formatting information is stripped off, keeping only text and likely only printable characters. Paragraph breaks will be translated to CR, LF or both (may depend on the platform). All remaining formatting is omitted, including page breaks, whether manually added or not.
If your ultimate goal is to study ODF, retrieve the standard describing the normalised XML encoding. But, anyway, don’t try to fiddle with any file encoding. It is really complex. Instead use Writer and learn styles which allow you to drive and control the formatting process in a rigorous, systematic and “professional” way.
Otherwise if you want to stuff any Unicode keypoint into a text file, use a text editor.