diff --git a/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md b/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
index 86f132e1..cc0b3475 100644
--- a/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
+++ b/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
@@ -323,3 +323,7 @@ names the principle that settles it, and is cited as "design 47 G A-n".
   `builder_stuck` all derive from it, and `builder_stuck` reads each build seat's steps through the seat (`<seat>.steps`)
   rather than a named module's state. The floor's sources are the holders of the seats `git` (tags) and `mesh-catalog`
   (requirements) on the seat list.
+- **A-83** (§374, A-78, A-80; principles 1 and 7) `BuildEdges.fp` is the fingerprint of the branch's catalog entry at
+  the revision `source` names, which the indexer holds itself; no field is added to `package-published`. For a build
+  of another watched branch, kind 1 compares with that branch's newest build, kept as heard in `heard` as
+  `branch-build.<module>.<branch>` (the digest `package-published` carries), not with a released digest.