Construction guys, I have a question- Entry door

I bought a 90 minute fire rated door to go between the shop and the house part of the Dust Bowl Headquarters. It has these straps on the sides of the jamb. What are they for?

 

google I was thinking along the same explanation as Mr Google. Cn,t think of anything else.

 

Interesting. I would have never figured that.

 

You have a masonry door the straps go in between the blocks that fit in side the door jam pm me if you have more questions

 

That makes sense. I am putting it in a wood 2x6 frame. I just didn’t want them rattling every time I shut the door.