1 - All .ci, and other base system utilites, e.g., gnu-utils, dpk-restore
2 - All .tar.gz the only write to /opt, /home/ and /tmp,i.e., unmodified liveCD system.
3 - All .dsl - causes mkwriteable to change base liveCD system, caution for low ram users.
4 - Any extension that overwrites base system files. Could possible affect the integrity of base system.