Perusing the schedule, I'm most looking forward to watching recordings of

https://debconf18.debconf.org/talks/112-civilization-runs-on-debian/
https://debconf18.debconf.org/talks/104-software-transparency-package-security-beyond-signatures-and...
https://debconf18.debconf.org/talks/72-how-debian-helped-translating-thousands-of-articles-in-wikipe...
https://debconf18.debconf.org/talks/14-debian-desktop-for-the-elderly/

Showing that I'm generally ignorant, I did not know about http://debdelta.debian.net/FAQ.txt which I will try shortly. Seen in description of https://debconf18.debconf.org/talks/66-delta-upgrades-revisited/