XF 2.1 Is there a way to know who is using which style?

[Spartan]

No

 

[Max Taxable]

Yes.

[OzzModz] Style Statistics for XenForo

Have multiple styles on your site? Wondering if some of them are just dead weight and not being used? This add-on tracks the actual styles your active members are using in real time when you allow style choices on your site. Features Style...

snogssite.com

 

[nocte]

If you talk about the users of your own forum: you can see each user's preferences in the admin control panel.

If you mean you saw a XF style on the web and want to know it's name, then you have to investigate the html source code.

 

[AndyB]

You might like this add-on:

https://xenforo.com/community/resources/style-info.6399/