diff --git a/docs/web/basics/guarantees.mdx b/docs/web/basics/guarantees.mdx
index b3c139e99..ebe7dbb14 100644
--- a/docs/web/basics/guarantees.mdx
+++ b/docs/web/basics/guarantees.mdx
@@ -77,11 +77,13 @@ exists.
 Retention is finite. [Cleanup](/maintenance/cleanup) prunes versions older
 than the retention window — **7 days by default** for `optimize()` in the
 embedded library, while a deployment's configuration sets its own. It always
-keeps the latest version, the versions branches were forked from and tagged
-versions. A tagged version that is older than the window and is not the latest
-stops cleanup altogether, until the tag is moved inside the window or deleted,
-or the window is widened. If you rely on reading old versions, widen the window
-before running it, not after.
+keeps the latest version and tagged versions. It also keeps the files a branch
+still reads, and the version the branch was forked from while the branch's
+remaining versions read the parent's files; after that, the fork version is
+pruned like any other. A tagged version that is older than the window and is
+not the latest stops cleanup altogether, until the tag is moved inside the
+window or deleted, or the window is widened. If you rely on reading old
+versions, tag them or widen the window before running it, not after.
 </Warning>
 
 **Dropping a table ends its history.** Versioning does not survive
diff --git a/docs/web/maintenance/cleanup.mdx b/docs/web/maintenance/cleanup.mdx
index ede712b2e..bd5b04731 100644
--- a/docs/web/maintenance/cleanup.mdx
+++ b/docs/web/maintenance/cleanup.mdx
@@ -40,8 +40,8 @@ removed, along with the files only they referenced. On a deployment, the
 retention period comes from its configuration instead.
 
 The latest version is never removed, whatever you pass. `timedelta(0)` makes
-every older version eligible for removal, but cleanup still keeps the versions
-that branches and tags protect, as the warning below describes.
+every older version eligible for removal, but cleanup still keeps tagged
+versions and the files branches still read, as the warning below describes.
 
 <Warning>
 Pruning is what makes [time travel](/management/table#versioning) finite: an
@@ -49,10 +49,15 @@ eligible version outside the retention window is gone. Cleanup keeps a version,
 whatever its age, when it is:
 
 - the **latest** version;
-- a version a **branch** was forked from, along with the files the branch
-  reads; the parent's other old versions are pruned as usual;
 - a **tagged** version.
 
+Cleanup also keeps the files a **branch** still reads, and the version the
+branch was forked from while the branch's remaining versions read the parent's
+files. That does not keep the fork for good: once the branch has replaced the
+data it inherited and its own older versions are pruned, cleanup prunes the
+fork version like any other. To keep a version recoverable, tag it, subject to
+the policy below, or keep the window wide enough to cover it.
+
 Under the default policy, a tag can also stop cleanup. When a tagged version is
 older than the window and is not the latest, cleanup refuses to run: it raises
 an error naming the tag and prunes nothing. To let it proceed, move the tag to a