javacript:history.back() is not a valid href attribute (lie!)

[mikeoptics]

Describe the bug
<a href="javascript:history.back()" class="underline">homepage</a>
causes a console error:
A11y: 'javascript:history.back()' is not a valid href attribute

But it is valid as its used to go back.

To Reproduce
See Here

Expected behavior
No error.

Information about your Sapper Installation:

Not relevant as it can be reproduced in REPL

Severity
Not even slightly

Additional context
Not just sapper but svelte too.

[Conduitry]

This was specifically added in sveltejs/svelte#4733. That's not to say this won't be reconsidered, but at one point this was considered a feature and not a bug.

[mikeoptics]

How ironic. I get it though and Il try using a11y ignore.