This file should be called .kateconfig, but it is named that way so as not to influence the editor.
kate: tab-width 4; indent-width 4; replace-tabs on;
kate: tab-width 4; indent-width oups; replace-tabs on;
kate-wildcard(*.xml): indent-width 2;
kate-wildcard(Makefile): replace-tabs off;
kate-wildcard(*.json;*.xml): indent-width 2;
kate-mimetype(text/x-c++src): indent-width 4;
kate-mimetype(*.xml) indent-width 4;
                    ^ not ':'