Any message that consists of a single word is a message of type symbol (as opposed to int or float or list or some other word followed by other items). The coll object explicitly puts the word symbol ahead of its output if the output is a single word. The advantage of that is that you can detect single-word outputs as being different from all other outputs, by using a route symbol object.
To automate file creation of similarly named stereo sound files (for example, soundbite1, soundbite 2, etc), this patch allows you to send the desired file name into the left inlet, then a 1 message to start recording into sfrecord~ and a 0 to stop recording. The audio you want to record is expected in the second and third inlets.