/usr/share/java/plexus-compiler-csharp-1.9.2.jar is in libplexus-compiler-1.0-java 1.9.2-6.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/java/plexus-compiler-csharp.jar
/usr/share/java/plexus-compiler-csharp.jar