A more thorough explanation:

A residuary devisee is a person named in a will who receives the remaining property of the testator after all other devises have been distributed. A devisee is a recipient of property by will.

For example, if a testator leaves specific gifts to their children and grandchildren, and then designates their friend as the residuary devisee, the friend will receive any property that was not specifically gifted to the children and grandchildren.

Another example would be if a testator leaves their entire estate to their spouse, but if the spouse predeceases them, then the residuary devisee would receive the entire estate.

Overall, a residuary devisee is an important part of a will as they ensure that any remaining property is distributed according to the testator's wishes.