The files you mention (/etc/bashrc and /etc/profile) are read at boot-time and somewher in them the env variables are exported. Further in /etc/rc.d/rc/sysinit the "foundations" of PATH are build with :
# Set the path
... and many more ...
somewhere in the beginning of the file. Perhaps that is the part you are looking for.
In addition some of the scritps in /etc/rc.d/rcX.d may start services which export their own env variables.
P.S. The above paths are taken from Red hat disto, I don't know if they are the same for Fedora and Debian.