As to why there is no /var/log/installer: I installed from a USB stick into a fully encrypted system, so that /var/log/installer file was on the sticks' memory file system, but not in the encrypted filesystem.
As to why there is no /var/log/installer: I installed from a USB stick into a fully encrypted system, so that /var/log/installer file was on the sticks' memory file system, but not in the encrypted filesystem.