A response to one of my previously raised Helpdesk requests - HD-19513:

This is the expected behaviour of Totara and there are no immediate plans to include this support. We are moving away from from using mustache template in favour of the new TUI framework so may not be very likely this will happen

Do we have any specific guidelines of when this move is likely to happen? We have a number of plugins that heavily rely on the mustache engine, so it would be good to have an idea to plan ahead. I'd imagine this will move in the format of deprecation for a specific period and then complete removal?