To Use Webhooks in specific branch

What Should I put in this input box guys?

I setted up webhooks with jenkins.

When I put it just blank that inputbox, works perfectly.

But the problem is works perfectly on every psuh event.

I want to make it work on ‘dev server’ branch push event only

I tried…

‘dev_server’ failed…
‘origin/dev_server’ failed…
‘refs/dev_server’ failed…
‘refs/head/dev_server’ failed…
‘refs/remotes/origin/dev_server’ failed…

I can’t even make it up word more… need help …