For the kerndat.fnt file inside any given font's directory...

The first line is in following format:
font_name leading char_spacing kern_amount vert_alignment

font_name is a string, all others are int.

font_name       (const char*)
	Directory name that contains the font glyphs, only used for debugging and organizational purposes
	
leading         (unsigned byte)
	The vertical distance between two lines from the top of the previous line to the top of the next line

char_spacing    (unsigned byte)
	The amount of space between each glyph when drawn onto the screen.

kern_amount     (unsigned byte)
	The amount of kerning applied, in pixels, when kerning is available.
	Can not be more than char_spacing.

vert_alignment  (signed byte)
	Aligns the font vertically on-screen in pixels
	positive numbers push the font down while negative numbers bring it up

Every line after the first corresponds to the kerning data
unicode_number kern_table

unicode_number  (5-digit hexadecimal)
	The number that corresponds to a specific unicode glyph in hex

left_kern_mask  (unsigned byte)
	0-3: left-hand side kerning mask

right_kern_mask (unsigned byte)
	0-3: right-hand side kerning mask


First few lines of the Zoq-Fot-Pik font's kerndat.fnt as an example:

zoqfotpik.fon 2 2 2 1
00020 3 3
00021 3 3
00022 2 2