Where to put a custom query builder?

Hi All, I'm fairly new to modern development coming from a rather simplistic mvc framework. While porting bits and pieces I wonder where to add my custom google analytics query builder. I see Laravel has a "Concerns" folder for its Eloquent querybuilder. I have initialised the googleapi in App\Services and use App\Repositories to get certain data sets where the fluent builder is currently housed. But I'd like it to be in its own spot to keep things clean.

Just an explanantion of the "Concerns" folder would be great, a google search didn't yield anything useful.

Cheers