These files were taken from the klick project under the GPL3. Its README says the following.
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Some of the audio samples used by klick have been borrowed (under
the terms of the GPL) from:
* Ardour [http://ardour.org/], sounds by Nick Mainsbridge
* GTick [http://www.antcom.de/gtick/], sounds by Roland Stigge
* Freepats [http://freepats.zenvoid.org/]
