Mystical secrets of the bookworm

∵ unmerged /usr is unsupported in bookworm and sid has been feeding bookworm since 2021-08-14,

unmerged /usr is also unsupported in sid since 2021-08-14,

no one using any portion of either bookworm or sid since 2021-08-14 should have any expectation that things should function correctly with unmerged /usr ,

∴ anyone using any portion of either bookworm or sid should execute apt install usrmerge or perform its equivalent on or prior to 2021-08-14.