Some time ago I've submitted a patch (https://git.reviewboard.kde.org/r/127291/) which forced opening text viewer instead of hex viewer when mimetype was unknown (application/octet-stream). This is of course valid only when TextMode is chosen in Konfigurator->General->Viewer/Editor. Situation got better but I still hit some corner cases when hex viewer is opened instead of text viewer.

Examples of corner case mimetypes I've found:

• application/x-extension-html
• application/x-trash

And there is probably more mimetypes not inheriting text/plain and therefore would lead to "binary" categorization.

I'd like to propose that when TextMode is enabled, every single file is opened in lister or text viewer regardless of it's mimetype. Hex viewer is never showed. Do you think it is a good idea?

Switch to TextMode and try:

• opening any text file using F3 key
• opening any *.bak or binary (e.g. png) file using F3 key