These audio files are BSD-licensed and were created/owned by the TrueOS Project:
 -   Login.ogg
 -   Logout.ogg

These audio files are freely available on jewelbeat.com:
"Music by JewelBeat. Download your free music and free sound effects at www.jewelbeat.com."
 -  low-battery.ogg (http://www.jewelbeat.com/free/free-sound-effects/musical%20effects/Tympani_2.mp3 - converted to OGG afterward)