The Linux source code is at the center of a court case once again, but this time, there’s no shadowy patent troll involved. The debate centers on VMware (VMW), which has been accused in Germany of improperly using open source code.

The origins of the case date back to 2007, when Christoph Hellwig, a Linux kernel developer, first alleged that VMware was violating copyright stipulations associated with the GNU Public License, which governs the Linux kernel code and a majority of other open source software projects. The complaints centered on VMware’s use of the Linux kernel as a key component of its ESX virtualization platform (and, later, the ESXi products that succeeded ESX), without publicly releasing the source code of the platform.

Hellwig has been supported by the Software Freedom Conservancy, which advanced additional charges against VMware starting in 2011, when it determined that the company was illegally using the source code for BusyBox, a set of open source tools that are packaged as part of VMWare’s virtualization products. The Conservancy is funding the current court case against VMware.

In their words, “Conservancy and Hellwig specifically assert that VMware has combined copyrighted Linux code, licensed under GPLv2, with their own proprietary code called “vmkernel” and distributed the entire combined work without providing nor offering complete, corresponding source code for that combined work under terms of the GPLv2. Hellwig is an extensive copyright holder in the portions of Linux that VMware misappropriated and used together in a single, new work without permission.”

VMware issued a statement on the case, which is based in Hamburg, Germany, to journalists that read, “We believe the lawsuit is without merit. VMware embraces, participates in, and is committed to the open-source community. We believe we will prevail on all issues through the judicial process in Germany.”

Like most legal cases involving open source software, this latest one is likely to be long and complicated. But it’s worth watching, since it stands to set important precedents for upholding the protections in the GPL, which requires developers who use GPL-licensed code to make the source code of derivative software publicly available. That’s a stipulation that’s difficult to enforce, not least because it’s hard to prove someone has used open source code in a project if he or she refuses to make the project’s code available to scrutiny.

Will VMware show us the code? Time will tell.