So its looks like a conventional field built (site built) truss - i have no verification of it being an engineer designed or approved construction. I will advise client not to attempt to modify it and that it is highly recommended to have an engineer evaluate it.
However, i will say here that there was a load of snow on it and it didn’t seem to be sagging at all.
I agree with the others. Like mentioned look for sags in the rafters. There isn’t much pitch to that roof so it would probably more likely visible with a lot of snow. Always check that those plywood gussets are attached well and none are missing.
If that’s 1/2" plywood and those rafters are more than 24" OC, the plywood is overspanned.
Leaks at the ridge, especially long-term leaks bad enough to soak the plywood gussets but not be visible from inside the home, can weaken gussets over time. Look for staining or decay indicating leakage.
Gussets are sound building build practice for furniture building .
1: No ridge beam and span is 4-8 feet? . Still over sized
2: Look at nails. Some are starting to transfer rust staining on to sheathing, meaning
a>there is a humanity problem but not evident on all nails.
b>Shingles are nearing there life span and or lack of under-layment at one time or now.
3: over spanned.
4: question the gable venting louvers being over-sized. Might allow weather to enter on windy days.
Any decking that widely spanned would need to be 1 to 5/4 ply.