The Musk-ovites are probably going to shut down the IRS publications because no one reads them.  But for now, there is Pub 559, and I found this with a 30-second Google search:

Earned income credit.

If the decedent was an eligible individual, you can claim the earned income credit on the decedent's final return even though the return covers less than 12 months. If the allowable credit is more than the tax liability for the year, the excess is refunded.

For more information, see Pub. 596, Earned Income Credit (EIC).