LDA #$28 / BIT $nnnn

It is a common convention in 6502 programming to allow easy
skipping over the next two bytes, to use the BIT instruction
(opcode $2C) for this. This allows code like:

entry1:
	LDA #$01
	.byte $2C
entry2:
	LDA #$02
	.byte $2C
entry3:
	LDA #$03
	...
	; Do something based on value of A

This works because the BIT $nnnn instruction eats the two bytes
that follows it as arguments, thus preventing the later LDA #$xx
instructions from being run.  This typically saves some bytes
compared to do it any other way.

It is used on all 6502 platforms, for example this discussion
on the trick for the Atari 2600:

http://atariage.com/forums/topic/100922-two-player-sprites-without-vdel/

It is not copyrightable.

Here is an example as we have used it to save space when determining
the correct width of a line:

	;;  Get pointers to screen/colour RAM source
	lda screen_line_link_table+0
	bmi +
	lda #40
	.byte $2C 		; BIT $nnnn to skip next instruction
	*
	lda #80
	sta load_or_scroll_temp_pointer+0
	sta load_save_verify_end_address+0

Only one of the LDA #40 or LDA #80 instructions will be executed.