The gateway software contains a rippled binary I believe. If so, they have distributed it.
There really is no "gateway software". There's just the rippled software. To my knowledge, we have not distributed the binary to anyone who has not also received the source. In any event, the only licenses the rippled software source code is subject to are:
1) The OpenCoin license.
2) The OpenSSL license.
3) The Boost license.
4) The LevelDB license.
5) The Bitcoin license.
Rippled also uses SQLite3 and json-cpp which are in the public domain. Additional licenses might apply to the JavaScript unit tests.
I stand corrected, thanks for clearing this up. The Ripple wiki
https://ripple.com/wiki/Rippled_build_instructions lists ctags
http://ctags.sourceforge.net/ as an optional package, which has a GPL license. Will this be respected, or does its optional status mean it is not necessary?