this fixes https://github.com/chrisaljoudi/uBlock/issues/1219 for Firefox

tools/make-firefox-meta.py

@@ -56,13 +56,13 @@ for alpha2 in sorted(os.listdir(source_locale_dir)):
 chrome_manifest = pj(build_dir, 'chrome.manifest')
 
 with open(chrome_manifest, 'at', encoding='utf-8', newline='\n') as f:
-    f.write(u'\nlocale ublock en ./locale/en/\n')
+    f.write(u'\nlocale ublock0 en ./locale/en/\n')
 
     for alpha2 in language_codes:
         if alpha2 == 'en':
             continue
 
-        f.write(u'locale ublock ' + alpha2 + ' ./locale/' + alpha2 + '/\n')
+        f.write(u'locale ublock0 ' + alpha2 + ' ./locale/' + alpha2 + '/\n')
 
 rmtree(source_locale_dir)