"cf." abbreviates the single word "confer", not multiple words

notes.md

@@ -146,7 +146,7 @@ need followup.
   commit and its becoming public can be seen?  Karl guesses that they
   do preserve all the metadata, but we should check.)
 
-  C.f. the situation with video game development, as Seth noted.
+  Cf. the situation with video game development, as Seth noted.
 
 * OPSI ["co-funding"](https://www.opsi.org/de/dokumentation/opsi-lizenz-und-copyright) (see also [this forum link](https://forum.opsi.org/viewtopic.php?t=1193))