diff --git a/etc/dnf/dnf.conf b/etc/dnf/dnf.conf
index 5ee578db..3548e5df 100644
--- a/etc/dnf/dnf.conf
+++ b/etc/dnf/dnf.conf
@@ -7,6 +7,9 @@ skip_if_unavailable=True
 
 # Fedora 40
 # https://fedoraproject.org/wiki/Changes/Drop_Delta_RPMs
+# Consider `sudo dnf install python3-dnf-plugin-cow` instead on 40+ and CoW
+# filesystem (btrfs, maybe xfs (untested)). Fallback likely slows down ext4.
+# https://fedoraproject.org/wiki/Changes/RPMCoW
 deltarpm=False
 
 # Explicitly enable finding the fastest mirror