virtualbox-guest-source 5.0.18-dfsg-2ubuntu1 (amd64 binary) in ubuntu xenial

 VirtualBox is a free x86 virtualization solution allowing a wide range
 of x86 operating systems such as Windows, DOS, BSD or Linux to run on a
 Linux system.
 .
 This package provides the source code for the virtualbox guest addition kernel
 modules. The virtualbox-guest-utils package is also required in order to
 make use of these modules. Kernel sources or headers are required to compile
 these modules.
 .
 The source is placed under /usr/src, and after decompression it can
 be built to produce a virtualbox-guest-modules-_KVERS_ providing
 "virtualbox-guest-modules" package.