code: static boolean isSigningRelated(String name) {
          name = name.toUpperCase(Locale.ENGLISH);
          if (!name.startsWith("META-INF/")) {
              return false;
          }
          name = name.substring(9);
          if (name.indexOf('/') != -1) {
              return false;
          }
          if (name.endsWith(".DSA")
                  || name.endsWith(".RSA")
                  || name.endsWith(".SF")
                  || name.endsWith(".EC")
                  || name.startsWith("SIG-")
                  || name.equals("MANIFEST.MF")) {
              return true;
          }
          return false;
      }
docs: true if file is part of the signature mechanism itself