Since this is an open-*source* project, we do have other options that seem to have no legal issues to me (IANAL).
Option A - Source only release with JDBC 4.0 based on proposed final draft Derby 10.2 release is source only, no pre-compiled jars, removes the dependency on the Mustang download. Option B - Release pre-compiled jars without JDBC 4.0 optional build Option A plus pre-compiled jars without JDBC 4.0, already supported by just compiling without a Java SE 6/Mustang JDK. In both cases the current state of the 10.2 branch is left unchanged wrt JDBC 4.0, ie. no removal of JDBC 4.0 from code or documentation. Dan.
