This is a program that is just like beep, except that instead of playing the sound to the PC speaker, it plays it via ALSA to, presumably, your sound card. This may be useful if you have a computer without a PC speaker, or if you want to test your beeping scripts using headphones to avoid annoying other people.
abeep incorporates some code from the original beep project. That project is © Jonathan Nightingale and released under the terms of GPL-2; the added code in abeep is © Christopher Head and is also released under the terms of GPL-2.