Describe the feature you would like to see.
Right clicking an unowned grave with a player head should cause that player head to be placed on the grave.

• The head will be removed from your inventory.
• Breaking the grave will return the head.

Commit 191bac0 adds this functionality.

There may need to be some tweaks here and there, I'm not completely
happy with the particles, but it seems to be working without issue.

In addition to the custom heads, I added support for adding the regular
minecraft heads/skulls. The dragon head still needs work, but I'll add
it later on.

Closing.