In this context, *safe* means the string encapsulates a known safe EcmaScript5 Expression (e.g., `(x + y * z())`).
Template authors are responsible for ensuring that typed expressions do not break the intended precedence and that there is no statement/expression ambiguity as when passing an expression like `{ foo:bar() }\n['foo']()`, which is both a valid expression and a valid program with a very different meaning.
Example: Given `hash = "619c16f"` defined in the front matter of your `.md` file: