diff --git a/etc/apt/sources.list.d/README.md b/etc/apt/sources.list.d/README.md
index 3e7d2740..19632c81 100644
--- a/etc/apt/sources.list.d/README.md
+++ b/etc/apt/sources.list.d/README.md
@@ -1,4 +1,5 @@
 # `/etc/apt/sources.list.d`
 
 The `.list` files are traditional, `.sources` are modern `deb822` formatted
-repository entries supported since Debian TODO and Ubuntu TODO.
+repository entries supported since apt `1.1` which is so old as to be
+difficult to find in 2025 considering Debian Buster (oldoldstable) is on 1.8.