ZeniMax Trademarks Hearth Fire, Possible Skyrim DLC?

The sleuths over at Fusible have discovered that Bethesda Softworks parent company ZeniMax Media has filed for a "Hearth Fire" trademark that they suspect is related to an upcoming DLC for The Elder Scrolls V: Skyrim. I guess we'll find out for sure in the coming weeks/months:
Earlier this month, ZeniMax Media filed a trademark application for Dragonborn. In April, the company filed for the dragon shout (Fus Ro Dah). Now, the company has submitted a new trademark application (Serial Number: 85634522) covering computer game software with the United States Patent and Trademark Office for (Hearth Fire).

(Hearth Fire) appears to be a reference to the skill book (2920, vol 09 Hearth Fire) in The Elder Scrolls V: Skyrim.

Skill books reward players with bonuses. Hearth Fire is a conjuration skill book and is part of the twelve volume 2920 books. The conjuration skill allows you to summon creatures from the dead or concoct ethereal weapons from soul energy.

The trademark application just appeared on the website of the USPTO today, and was originally filed on May 24, 2012.

At this point, it's unknown whether Hearth Fire will be for a new Skyrim DLC, a new video game, or something else.
Thanks, Strategy Informer.