Passing arbitrary data to href attributes

[btpy]

Hi!
when i'm defining and href attribute with square brackets, e.g.

<a style="color: #ffffff; -ko-color: @[Color.readability(linkStyle.color, backgroundColor) gt 2 ? linkStyle.color : (Color.isReadable('#ffffff', backgroundColor) ? '#ffffff' : '#000000')]; text-decoration: underline; -ko-color: @linkStyle.color; -ko-text-decoration: @linkStyle.decoration" href="[unsubscribe_link]" data-ko-editable="disiscrivitiText">Unsubscribe</a>

the href attribute stays the same, but if I change brackets to curly href is mutated to:

https://domain/path/{unsubscribe_link}

Is it possible that href="{unsubscribe_link}" stays the same?
Thank you