What do I do to get in the window in the attachment?

Hello everyone. How are you?
I'm a bit embarrassed but I have to ask. It's been a while that I wanted to but as I've said is a bit embarrassing. What is this in the attached screenshot?
I happens some time and the only way that I've been able to figure out to make it disappear is by clicking on my project in the media window. 
I'm afraid that I'm going to do something wrong anytime soon and I'd like to know about it and a... dignified way of going back, if possible?

Thanks so much for your help once more
Best regards!

Oscar

It looks like you've either opened a clip and what you're seeing is the part that's used in the project or possibly a compound clip and you're seeing the same thing. Click the button beside the word 'Bring' and it will take you back to your project. 

Yep, that's a compound clip.  The icon in the upper-left corner gives it away.

OP, double-clicking on the compound clip in your main project will open this view - it's kind of like a nested sequence if you're familiar with those.

This info about Compound Clips might be helpful. support.apple.com/guide/final-cut-pro/in...lips-verbbd3496b/mac

Thanks so much, dmetz. I see the icon now I don't know how I get normally there. I suspect of a wrong shortcut.
Best!

Great TerryB! 
Thanks!

Thanks so much, Doug!