This file is indexed.

/usr/lib/mono/4.5/Microsoft.Build.Engine.dll is in libmono-microsoft-build-engine4.0-cil 4.2.1.102+dfsg2-7ubuntu4.

This file is owned by root:root, with mode 0o777.

It is a symlink to /usr/lib/mono/4.5/../gac/Microsoft.Build.Engine/4.0.0.0__b03f5f7f11d50a3a/Microsoft.Build.Engine.dll