diff --git a/etc/pki/ca-trust/source/anchors/README.md b/etc/pki/ca-trust/source/anchors/README.md
new file mode 100644
index 00000000..c9d61d2d
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+++ b/etc/pki/ca-trust/source/anchors/README.md
@@ -0,0 +1,5 @@
+Fedora & SailfishOS: drop `.pem` files of root certificates here and
+`sudo update-ca-trust`.
+
+Debian & co: drop `.crt` to `/usr/local/share/ca-certificates/extra/`
+(create if doesn't exist, `/extra/` may be anything) and run `sudo update-ca-certificates`