I have just created a new user in my computer and logged in his account only using this computer (Ubuntu and I used the chrome browser). In this computer, I have used only Chrome and Mozila, but never Safari (I guess there is no Safari for Ubuntu, but anyway I didnt use it). I got this from email in a feedback form from this user:
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/39.0.2171.65 Chrome/39.0.2171.65 Safari/537.36
Note that Safari seems to be there! Since it is being used @$_SERVER['HTTP_USER_AGENT'] I could expect Mozila, since the same computer logged in this site using Mozila, but never Safari.
What must be happenning? Is this correct?