Bottom chord bracing: temporary or permanent?

We have a home built in 2008 with a truss roof over the garage. There’s 1×4’s that run the middle of the bottom chords, which I believe is a rat run. There are also 1×4’s running diagonal from the middle to the corners.
I think these are probably temporary braces, since most guidelines I’ve seen stipulate 2×4’s for permanent bracing.
I’m running Ethernet cable through our attic and I’d like easier access so I’m putting in a pull-down ladder. However, the ideal location for the ladder would interfere with one of the diagonal 1×4’s. I’ll be adding a 2×4 header very close to where the 1×4 is.
Any thoughts on whether or not this board is permanent or temporary? Is the header sufficient for providing any bracing the 1×4 is doing?
Replies
1x4’s are actually approved for a lot of bracing, but depends upon design of when/where you can use them. The diagonal boards are lateral bracing probably (w/out eyes on it hard to say) and very necessary. Can you get your hands on the blueprint for trusses? That will tell you everything. You could always take a board off while you do your work and reinstall after if you do not have extreme winds, snow ect creating stress on the roof at the moment.