Hi, sorry for the late response here.

I'm a product manager at Totara, working on the core platform and areas such as this.

When it comes to Totara development, we favour Vue for front-end development using the TUI framework. As such, this is where our effort goes, but I can confirm that we have no plans to drop support for mustache at this stage.

Should this happen in the future, we would follow our standard deprecation guidelines and advanced warning as noted here: https://totara.atlassian.net/wiki/spaces/DEV/pages/121187267/Deprecation+guidelines