/usr/lib/mono/4.0/xsp4.exe is in mono-xsp4 2.10-2.4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/mono/4.0/../gac/xsp4/2.10.0.0__0738eb9f132ed756/xsp4.exe
/usr/lib/mono/4.0/../gac/xsp4/2.10.0.0__0738eb9f132ed756/xsp4.exe