Computation of the unique genes per assembly provided by the quality report

[olar785]

Hi Mathew, this is more of a question regarding the quality report but I thought I would post it here in case it is of interest to others.
The quality report produces the following:

***** UNIQUE GENES ORP ~~~~~~~~~~~~~~~~~> 10278
***** UNIQUE GENES TRINITY ~~~~~~~~~~~~~> 9393
***** UNIQUE GENES SPADES55 ~~~~~~~~~~~~> 9058
***** UNIQUE GENES SPADES75 ~~~~~~~~~~~~> 8617
***** UNIQUE GENES TRANSABYSS ~~~~~~~~~~> 10617

From reading the manuscript and the documentation, it is not clear to me what the number of unique genes represent and how it is computed. Transrate does provide the number of unigenes (I believe used interchangeably with contigs) so I first thought it represented the number of unique contigs but the final assembly I get from ORP contains a little over 218,000 unique sequences. As such, I imagine the unique genes presented in the report are contigs that could be assigned to a certain database? Clarity on how this output is generated would be greatly appreciated.
Many thanks,
Olivier