The sed command (right, it needs sudo, sorry about that) blacklists r8168 instead of r8169.
Explanation: installing r8168 also creates file /usr/lib/modprobe.d/r8168.conf which blacklists r8169.
Now this sed command simply changes that file to blacklist r8168 instead.
This also means r8169 is used, not r8168.
This way we can keep installing r8168 package with these Ethernet cards, but by default system uses r8169.
And the r8168 package is available if network doesn’t work with r8169.
User just needs to reinstall r8168 and reboot.
Not sure we will use this, but interesting to see the results.