How does this circuit work? Is it a pre-amp?

[Jasen Betts]

The paper also says: "L2 is 112nH (this tunes to the middle of the FM
band, 98 MHz), with C13 at its center value 33pF. L2 is 5 turns of 22
swg enameled copper wire close-wound on a 5mm diameter former. You can
also have a fixed 33pF capacitor instead of the variable C13 and have
L2 as an adjustable molded coil."

... btw, what's a "former"?

something to wrap the wires round.
A 5mm drill bit would work (and willbe exactly 5mm) 22swg is stiff enough
to hold its shape after the bit is withdrawn. (leaving the drill bit
in place would foul everything up)