use by users is strongly discouraged, because their scoping
semantics can be confusing.
-When the value of such a variable is changed in a @code{.ly} file,
+When the value of such a variable is changed in a @file{.ly} file,
the change is global, and unless explicitly reverted, the new value
will persist to the end of the file, affecting subsequent
@code{\score} blocks as well as external files added with the