The Gravestones plugin was finally updated it to 1.11. I tested it out this morning and it works as expected, with one glitch. It doesn’t work in areas protected by WorldGuard, such as the spawn. I informed the developer about this bug and haven’t heard back from him yet.
The way Gravestones works, is when you die, it creates a marked grave where all of your belongings are stored, and only you can get to them. You have thirty minutes to return to your grave and dig up your items. You may also have to defeat your own zombie to get your items back.