Arch License
Arch is licensed under a CSIRO OPEN SOURCE SOFTWARE LICENCE if you are in Australia or a GNU GENERAL PUBLIC LICENSE if you are outside Australia, subject to one exception in both cases:
We ask you to retain a clearly visible link to Arch home page (http://www.atnf.csiro.au/computing/software/arch/) with text "Powered by CSIRO Arch" or the Arch logo image as the anchor on all pages generated by Arch or other software that uses Arch or parts of it as component(s).
The full text of both licenses is included in the package. The licenses are very similar, but note that the CSIRO license makes an additional statement required by the Trade Practices Act in Australia.