I used Manage Jenkins to download the seleniumhq plugin, and do a jenkins restart.

While configuring a job, the question-mark icons normally allow you to get help about the nearby field. This continues to work fine for the fields that were there before. With the new seleniumhq-specific fields, the question-mark icons all return:

ERROR: Failed to load help file: Not Found

The system log has nothing helpful.

I've never used this plugin before. A pointer to the contents of those files would be almost as nice as a bug fix.