Notes not showing up, but SQD files are there - how to import?

I used to use Carnet for quite a while, but some day many of my notes vanished from the app both on Android and in Nextcloud, and one of the remaining notes was only shown on parts.
I didn’t find a way to restore them and thus turned my back on Carnet.

But now I found that the files with my notes apparently still exist - file names have a .sqd suffix and seem to contain HTML and some extra chars that make Linux think it may be a binary file.

Is there a way to import these files into Carnet again?

Check carnet git repo directly and search against issues, or file as needed.