Something Strange has been going on with my new Windows 10 installation. Firefox?

    I decided to reinstall my system from scratch, mainly so that I could install nothing but Windows 10 and my Sonar software and plugins and get everything activated, and make an Image backup with everything activated in the case I might have to reinstall later on. As to how that might work with a different hard drive if this one crashes and all that stuff goes, I have no idea.
 
Anyway, I reinstalled my system fresh from Windows Official download .ISO area and all of that stuff. 
 
What I find very strange, I keep noticing that "Firefox is installed also"?  I removed it right away because I don't use it for one and secondly I use Opera. I hate GOOGLE! 
 
I can't figure out how Firefox ended up on a fresh install of Windows 10?  
 
Nobody but me uses this PC.  
 
I am curious though, I did give Firefox a try about 3 months back, so I wonder if this new microsoft syncing crap didn't put it there with my new install. 
 
I have no idea, and when I mention this being on my PC, I mention it right after formatting the hard drive and reinstalling Windows 10 from scratch and it is there. 
 
I just find it very odd. I have no idea why it would be there.
 
Any idea's on this one? Maybe it's a sync thing is all I can figure. 
 
Thoughts? 
 

TheSteven
Chrome is Google, FireFox is by Mozilla and as of the latest version has become my favorite browser.
Microsoft is pushing it's Edge browser so they wouldn't just 'slip-in' FireFox on you.
 
The only thing that comes to mind is did you install either Adobe Flash player or Java updates?
Both of those regularly bundle crap with their installers that if you're not vigilant will pollute your system.
 

Thank you TheSteven, more than likely that probably was what happened. I did install Adobe Flash, perhaps I missed unchecking something somewhere and that's how it got installed. That's the only thing that I can think of as to how it happened, but what is weirder about it is that however it got on my system it didn't create a desktop icon, I just ran across when I was looking at the folders. 

Thanks again.