row 264a r5 (#1769): build notes name the op rename to legacy-3l and migration-3l by the step's target version (sage-2415)

agents/gizmoduck/work/queue-264/BUILD.md

@@ -228,8 +228,9 @@ Row 236 (8f51900b5, which round 5 is built on) adds `migrations/3j-3k.sql` with
 sage-2412) 264a's step moves one version. The design above still says 3j-3k; read it as 3k-3l.
 
 - `migrations/3k-3l.sql` is round 4's `3j-3k.sql` with three renames and nothing else: the copy
-  tables are `*_3k`, and the op values are `legacy-3l` and `migration-3l`. A step named for the
-  version it leaves should not write a value naming another one.
+  tables are `*_3k`, and the op values are `legacy-3l` and `migration-3l`. The op values name the
+  step's target version, as round 4's `legacy-3k` did on 3j-3k (sage-2415). No earlier migration
+  set a precedent either way.
 - store.mjs runs 236's 3j to 3k step, then 3k to 3l. `SCHEMA_VERSION` is `3l`, and
   `SCHEMA_SHA256` is the merged schema.sql's, cd68512212ce8bf8f5631138b2e63a340fa7b940088430649bb7784af7df162a.
   schema.sql merged with no conflict: 264a's edits are above 236's two tables at the end.