It is up to each copyright holder to decide how they will enforce the licence for their code. Mambo has always been licensed under the GPL and the Mambo Licensing Guidelines set out the Foundation's position with respect to enforcement of the licence over its code.
To the extent Mambo includes code owned by other licensors, it is a matter for those licensors as to how they will enforce their licence. Third party developers should therefore always obtain their own legal advice as to whether their licensing model is appropriate given the way that their software interacts with Mambo or other software licensed by third parties.
It is our opinion that use of Mambo interfaces does not make “derived works” per se. Function calls to the Mambo API do not, in themselves, create derived works. This is the Mambo Foundation's position in relation to the use of Mambo code. Please note that other licensors may have a different position.
A court will ultimately have to decide the issue should another licensor seek to enforce its interpretation of the GPL on its licensees.
You can read the Licensing Guidelines in the legal section of the Mambo Foundation's website here:
http://about.mambo-foundation.org/in...nse-guidelines