I'll bite.

From your photograph it appears that the roof framing is comprised of some form of metal-plate-connected wood trusses. In addition, there is dimensional lumber of a varying color installed within and along the trusses, some of which is oriented similar to truss bracing.

Beyond that I can't tell you much from my desk with one photograph. I don't even know what the scope of the planned roof repairs are. Is there known moisture issues and rotted deck and/or framing? Maybe some of this is old repairs for recurring moisture issues? Maybe its an old retrofit/reconfiguration of the space? Can't tackle this as a keyboard warrior, you would need eyes on site to get an accurate answer.

Can you get the original structural engineer to take a look? It might be obvious with a site visit what the purpose of all of this is/was.

Agree with Luk, can't tell much from the photo, some context of what these additional braces are intended to provide would be helpful.

How old is this structure? The truss nail plates look strange, who is the manufacturer, and are there any manufacturing details on the plate? Is it just a piece of sheet metal that has been nailed through from the chords to the webs?

I can't give any advice on the structure either, but be careful of that loose insulation. It may contain asbestos or other respiratory hazards.