What are custom attributes for?

Hey Guys !
Just wanna know what are the custom attributes for, I didn’t find any information in the documentation.

Can someone give me more information about it?

Thank you.

@ThibaudF I realise it’s been a while since the question was posted, and the docs have been updated numerous times since, but here is a link to the documentation that might be able to shine some light on the matter. Let me know if further help is needed on this.