McKoi is a pure Java database that was originally distributed under GPL2 (newer versions are released under GPL3), while Fedora is distributed under Apache2.
Fedora has never depended on McKoi in order to run – it has always been an option. As of Fedora 3.2, the database itself was no longer distributed with Fedora (we switched to Derby as the out-of-box native Java database), but we continued to support integrating with a pre-installed McKoi database.
Although this is only the JDBC driver, and is only provided as an option, there is still legitimate concern that the license of the older version of McKoi (whose JDBC driver we have distributed in the past) is incompatible with Fedora.
To allay these concerns, we have two options:
1) Implement and test compatibility with the newer version of McKoi, which is under GPL3, so we can include the driver and make it easy for people to use at install-time, or
2) Completely remove McKoi support (no JDBC driver, install option, or DDLConverter)
I favor option #2 since we already have a pure Java database that works fine out of box (Derby), and it's unlikely that anyone is still using McKoi – even if they were, it's not difficult to use the rebuilder to migrate to Derby.