Someone tried to use my unit testing framework and it wouldn't build. When I looked at the log everything worked well until near the end where there werethese entries. I've elided just one of them here for brevity.
At some point along the way (I am the culprit here) I had installed Mylin Javascript Development support. This was done as there were some dependencies I needed to satisfy with version control integration (GALILEO).
I removed the support for Javascript and the problem disappeared.