[$] Seeking the endgame for Debian's /usr merge

Like most other distributions, the Debian project decided to end theseparation between the root and /usr filesystems years ago.Unlike most others, though, Debian is still working on the implementationof this decision. The upcoming Debian 12 ("bookworm") release willfeature a merged /usr in most respects, but there are a couple ofnagging issues that threaten to stretch this transition out for some timeyet.