Importance of GNAT.Source_Info

[Jere <jhb.chat@gmail.com>]

I'm working on a baremetal RTS and while looking at
https://wiki.osdev.org/Ada_Bare_bones, one of the files
it suggests is part of the minimum set of RTS files is
g-souinf.ads which contains the package GNAT.Source_Info.

Does anyone know what part of the compiler requires this?
So far I haven't had GNAT barf at me for not having it
while compiling the files I do have, but I don't want to 
leave it out if it is indeed necessary for something.  I
didn't see any info on why it is necessary.  It's definitely
useful in that it gives a lot of compile time values, but
not sure why it would be a "required" file.  I'm assuming
something will break without it, but don't know what.

Sorry that this isn't a pure "Ada" question and is more
focused on GNAT specifically, but thought one of yall
might know why.