1274:978 Opera?

Suddenly the top bar which normally just says Opera now says 1274:978 
since yesterday.  I haven't installed anything for a few days.  I've 
got both 9.23 and 9.24 versions of Opera and both display the same.  
Other browsers don't display this.  So I deleted the plist file in 
Preferences, and it was the same when restarted.  Then I deleted the 
whole Preferences file and it was gone.  Anybody know what this means?