Comment 0 for bug 947236

/etc/os-release is a new upcoming attempt of a standard which is meant to supersede /etc/debian_version, and their counterparts in Fedora/SUSE: http://www.freedesktop.org/software/systemd/man/os-release.html

/etc/lsb_release is similar to this, but not standardized. The standard interface right now is to call lsb_release which is a Python script and thus a very high overhead compared to merely reading a file.