After last Update, I found that html-pages were connected to KATE; no problem, I changed it in SystemSettings > text > html. That works.
Nevertheless, if I click an URL (in AKREGATOR), f.e. http://localhost:8111/import?url=https://www.openstreetmap.org/api/0.6/relation/12276395/full (that should direct into JOSM) again KATE is started.
How to fix this?
Thank you, Michael