There's a picture of a box with a bunch of playing cards on top of it, then a picture of a building that has one. I found it insufficient and thought others might too.
Offering clarification is good, shitting on the article is bad.
The article does, in fact, do a perfectly fine job of explaining what a swift brick is. GP could easily have said “I couldn’t quite picture what a swift brick is”, but instead said “article did a poor job explaining swift bricks”, and that’s what they’re getting criticised for.
Literally right below the title:
> bricks that provide nesting for swifts and other endangered birds
And a picture.