What is this...?

I don't remember sending just a period (.), so I checked again and realized I had written a long comment, but why only a period...? Is it because it was an edited comment? Or is it because it was too long...? I covered up the nickname part because it mentioned someone else's nickname, just in case. But seriously.. what is that period? + Ah, I rechecked and found that a sentence had been carried over after the period. I deleted the period and moved the sentence forward, and it was resolved. But I don't remember writing that period, when was it written?