diff --git a/docs/usage/configuration-options.md b/docs/usage/configuration-options.md
index 0c5fe8e0b20c3eb78c5275f10bfeb2655e768f4a..97c5aa2c91249a905829cbfad94897b1d25c9898 100644
--- a/docs/usage/configuration-options.md
+++ b/docs/usage/configuration-options.md
@@ -3512,8 +3512,19 @@ Set `pruneBranchAfterAutomerge` to `false` to keep the branch after automerging.
 
 ## pruneStaleBranches
 
-Configure to `false` to disable deleting orphan branches and autoclosing PRs.
-Defaults to `true`.
+By default, Renovate will "prune" any of its own branches/PRs which it thinks are no longer needed.
+Such branches are referred to as "stale", and may be the result of Open, Merged, or Closed/Ignored PRs.
+It usually doesn't _know_ why they're there, instead it simply knows that it has no need for them.
+
+If a branch appears stale but has been modified by a different git author, then Renovate won't delete the branch or autoclose any associated PR.
+Instead, it will update the title to append " - abandoned" plus add a comment noting that autoclosing is skipped.
+
+If a branch appears stale and hasn't been modified, then:
+
+- If an Open PR exist for the branch, then Renovate will rename the PR to append " - autoclosed" before closing/abandoning it
+- Renovate will delete the branch
+
+You can configure `pruneStaleBranches=false` to disable deleting orphan branches and autoclosing PRs, but then you will be responsible for such branch/PR "cleanup" so it is not recommended.
 
 ## rangeStrategy