just need to backup this file,
~/.jmonkeyplatform/3.0/config/org-netbeans-api-project-libraries/Libraries/jme3-libraries.xml
I found the libs here:
grep “libs.jme3-libraries.classpath=” ~/.jmonkeyplatform/3.0/build.properties |tr “:” “\n” |sort
created a new global library: jme3-libraries-BKP
and copied ~/.jmonkeyplatform/3.0/config/org-netbeans-api-project-libraries/Libraries/jme3-libraries-BKP.xml
to the missing one, editing inside of it by removing “-BKP”