So I was trying to hack a model for Insurgency 2, replacing the default helmet for Security with some helmet from MW2.
I got all the modelling stuff out of the way, and then I got to editing the .QC file.
I did all the stuff necessary, but I noticed these weird lines pertaining to some bones.
I'll try to do a basic summary of how they were written, but here is what they said:

solid
{
"(bone/joint name)"
x
y
z directions
weight or something like that
}

And then it had lines called 'ragdollconstraint' below it, and they all contained numbers instead of joint names.
Crowbar definitely didn't know what both solid and ragdollconstraint were, and issued a badcommand 'solid' when I tried to compile the model.

Does anyone know if this is Crowbar's fault, or something else related to the QC?

I also tried deleting them, and it compiled the model just fine. Loading it in game crashed it.