Content fragment metadata is blank in AEM 6.5

[venkateshg]

when we try to open metadata of content fragment model it shows blank page.below is error.

29.03.2020 18:03:53.904 *ERROR* [0:0:0:0:0:0:0:1 [1585519433898] GET /mnt/overlay/dam/cfm/admin/content/v2/metadata-editor.html/content/dam/we-retail/my-cf-sample HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Uncaught SlingException
java.lang.NullPointerException: null
at org.apache.jsp.apps.cq.gui.components.authoring.editors.core.includeCssLibs_jsp._jspService(includeCssLibs_jsp.java:163)

[Jaideep_Brar]

You seem to have an overlay at "apps/cq/gui/components/authoring/editors/core/includeCssLibs" where the nullpointer is observed. Either delete this and recreate this overlay from /libs or try to find which line is throwing nullpointer