Source code for innerhtml.bind

Greetings.

May I ask where in Aurelia 1’s codebase is the source code for whatever powers innerhtml.bind (a custom attribute?).
Additionally, does Aurelia provide a way to directly bind a HTMLElement stored in a property to the DOM?

Thank you in advance.

Note: I have found an alternative option and I do not require an answer anymore. I am leaving this open in case anyone is interested.