diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c78ed997..736fc374 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -174,6 +174,23 @@ created a carve out to the 2-ACK rule.
 A PR may be considered for merge if it has a single ACK and has sat open for at
 least two weeks with no comments, questions, or NACKs.
 
+#### One ACK carve-out
+
+We reserve the right to merge PRs with a single ACK [0], at any time, if they match
+any of the following conditions:
+
+1. PR only touches CI i.e, only changes any of the `test.sh` scripts and/or
+   stuff in `.github/workflows`.
+2. Non-content changing documentation fixes i.e., grammar/typos, spelling, full
+   stops, capital letters. Any change with more substance must still get two
+   ACKs.
+3. Code moves that do not change the API e.g., moving error types to a private
+   submodule and re-exporting them from the original module. Must not include
+   any code changes except to import paths. This rule is more restrictive than
+   the refactor carve-out. It requires absolutely no change to the public API.
+
+[0] - Obviously author and ACK'er must not be the same person.
+
 ## Coding conventions
 
 Library reflects Bitcoin Core approach whenever possible.