nojoda
Home / Highlight paragraphs - EPUB Files
GitHubRulesOK
Highlights are appended to PDF as defined by PDF Standard, however there is no similar function for appending highlights into ePub in MuPDF.
SumatraPDF older pre-release versions prior to 3.2 version had such an experimental highlighting feature and you can still write your own .smx for use with 3.2 portable, see Annotate (highlight / add comments) with SumatraPDF - #7 by GitHubRulesOK
Note that trial feature is unlikely to be revived as coding conflicted with PDF highlights, so for now that’s as good as it can be / was.