Agreed in team meeting today: Our current in-house interpolation format for messages requires more maintenance work and is limited in expressivity.

It could be replaced by either Fluent v1 or MessageFormat v2, depending on which one is the most relevant when we get to it.

At the moment, Fluent seems to be more attractive (more readable, more official bindings, React element interpolation).

In any case, it seems wiser to wait for React conversion to be complete before starting this other related conversion. It will also require converting a fair amount of messages and translations to the new chosen syntax.