Ah! From Janet Furman's website:
I designed the preamp power supply, circuit board, and rackmount chassis. I called it the F-2B. “F” was a tribute to Fender, whose Twin Reverb triode preamp stage inspired it. “2” because it had two channels, and “B” because the first circuit board layout, designated “A”, had problems and had to be re-done. Alembic turned this into a successful product that they still sell today, 40 years later. I doubt they remember where the name came from.