Putting the FU in SNAFU

My problems decrypting* abbreviations have been documented. But here's one I found to be a stumper. My wife and I pulled into Arby's yesterday to see this on the marquee:

TRY OUR MF GYRO

Says I: "What do you think the MF stands for?"

While the obvious, yet slightly inappropriate, answer to the question loomed in our minds, we scoured the building for clues. A full-color banner proclaimed "New Roast Beef Gyro!" No, that would be an "RB GYRO".
We tried talking it out:

Hmmm,
Most Fabulous?
Magically, um, Flavored?
(trying to sneak up on it) Mmm...marble...uh...fff... uh, fff.. forget it. It makes no sense.

I decided that MF(in') Gyro! was actually not a bad name for a sandwich.

Today, I googled "MF Gyro" and got diddly. The Arby's site doesn't mention it. But, I think I figured it out. They've got a line of sandwiches called "Market Fresh". That must be it.

Note to Arby's: Your Market Fresh line isn't well-known enough to initialize. And if it ever does become well-known, I don't know if "MF Sandwiches" has the ring you're looking for.

If Arbys' corporate is reading this, you should call the Arby's in Coopersville and ask them to change their MF sign.

*de·crypt tr.v. de·crypt·ed, de·crypt·ing, de·crypts
1. To decipher.
2. To dig up (see mummy,).