Where is this stray bracket coming from?

I have searched through my code and I can’t find it. I tried searching with this regex: [^}]}[^}]

Have a look at the screenshot below, taken from my Chrome console.

DeepinScreenshot_select-area_20180211090559

Any ideas on how I can find it? Or is this some kind of Meteor bug?

What templating system are you using on the front end?

To me that looks like what happens in Blaze when a stray curly is in a <head> tag. Because Blaze merges all the head sections together it would end up like that

I am using Blaze. However, there is no bracket in the section.