NDesignDict semaphore

My domino server or console displays this message:

ti = “004E1772-24257D6D” sq = “0000067A” THREAD [130C: 001A-07B8] WAITING FOR WRITE LOCK ON FRWSEM 0x3A0B NDesignDict semaphore (@ 0DFC2034) (R = 0, W = 1 = 130C WRITER: 1B60,1STREADER = 0000: 0000) FOR 30000 ms

I can not find documentation on the semaphore NDesignDict.

Any information on this is appreciated