-You are not required to define a variable in order to use it,
-but the definition can supply documentation and an initial value
-in a way that tags can recognize.
-
-INITVALUE is evaluated, and used to set SYMBOL, only if SYMBOL's value is void.
-If SYMBOL is buffer-local, its default value is what is set;
- buffer-local values are not affected.
-INITVALUE and DOCSTRING are optional.
-If DOCSTRING starts with *, this variable is identified as a user option.
- This means that M-x set-variable recognizes it.
- See also `user-variable-p'.
+You are not required to define a variable in order to use it, but
+defining it lets you supply an initial value and documentation, which
+can be referred to by the Emacs help facilities and other programming
+tools. The `defvar' form also declares the variable as \"special\",
+so that it is always dynamically bound even if `lexical-binding' is t.
+
+The optional argument INITVALUE is evaluated, and used to set SYMBOL,
+only if SYMBOL's value is void. If SYMBOL is buffer-local, its
+default value is what is set; buffer-local values are not affected.