Okular is the best all round file viewer and extraction utility in the absence of OCR software. Until recently I had been using Okular on FerenOS and today I was asked to look at a Braille guide that someone had prepared for others to refer to when following a specific learning guide for youngsters. I applied some review ‘post-it’ note pins and attempted to save as an Okular archive - it crashed. I looked in the Software Channel and found a flatpak version - removed the standard install and backends then installed the flatpak version and all of the four backends for okular - now no issue.