What does it mean "status:unknown" for a LibreOffice extension?

I wrote an extension. While i load it to LibreOffice 5.3 master, after i accep the license it gave me “the status of this extension is unknown” error. And i can’t enable it. When i check it with unopkg i see that output:

Identifier: com.x.x
  Version: 1.0
  URL: vnd.sun.star.expand:$UNO_USER_PACKAGES_CACHE/uno_packages/lu1019513n4t0.tmp_/x.oxt
  is registered: unknown
  Media-Type: application/vnd.sun.star.package-bundle
  Description: x

  bundled Packages: {
      URL: vnd.sun.star.expand:$UNO_USER_PACKAGES_CACHE/uno_packages/lu1019513n4t0.tmp_/x.oxt/X/
      is registered: no
      Media-Type: application/vnd.sun.star.dialog-library

      URL: vnd.sun.star.expand:$UNO_USER_PACKAGES_CACHE/uno_packages/lu1019513n4t0.tmp_/x.oxt/Addons.xcu
      is registered: yes
      Media-Type: application/vnd.sun.star.configuration-data

What does it mean “registered: unknown” or “registered: no” ?

script.xlb and dialog.xlb files was missing. After i add them the problem solved.