in src/main/java/org/apache/sling/javax/activation/internal/Activator.java [58:86]
    public void start(BundleContext context) throws Exception {
        commandMap = new OsgiMailcapCommandMap();
        for (Bundle bundle : context.getBundles())
            registerBundleMailcapEntries(bundle);
        CommandMap.setDefaultCommandMap(commandMap);
        bundleTracker = new BundleTracker<>(context, Bundle.ACTIVE | Bundle.UNINSTALLED | Bundle.STOP_TRANSIENT,
                new BundleTrackerCustomizer<Void>() {
                    public void removedBundle(Bundle bundle, BundleEvent event, Void object) {
                        unregisterBundleMailcapEntries(bundle);
                    }
                    public void modifiedBundle(Bundle bundle, BundleEvent event, Void object) {
                        unregisterBundleMailcapEntries(bundle);
                        registerBundleMailcapEntries(bundle);
                    }
                    public Void addingBundle(Bundle bundle, BundleEvent event) {
                        registerBundleMailcapEntries(bundle);
                        return null;
                    }
                });
        bundleTracker.open();
    }