Disabling of filecheck is not actually possible because btw it cause the attachment.pm to malfunction and any of pagespec that could contain a *mimetype* condition. attachment.pm imports "statically" filecheck so actually disabling it should be *interdicted* .
sub import {
        add_underlay("attachment");
        add_underlay("javascript");
        add_underlay("jquery");
        hook(type => "getsetup", id => "attachment", call => \&getsetup);
        hook(type => "checkconfig", id => "attachment", call => \&checkconfig);
        hook(type => "formbuilder_setup", id => "attachment", call => \&formbuilder_setup);
        hook(type => "formbuilder", id => "attachment", call => \&formbuilder, last => 1);
        IkiWiki::loadplugin("filecheck");
}