A more thorough explanation:

in rebus litigiosis

When something is subject to litigation, it is said to be "in rebus litigiosis." This means that there is a legal dispute or lawsuit involving that thing.

• A house that is being fought over in court is "in rebus litigiosis."
• A company that is being sued for patent infringement is "in rebus litigiosis."

These examples illustrate the definition because they both involve legal disputes. The house and the patent are both things that are being fought over in court, which means they are "in rebus litigiosis."