When I was looking the Total.js messenger sourcecode, I noticed the "@{...}" placeholder in the HTML markup.
https://github.com/totaljs/messenger/blob/master/views/index.html
What kind of placeholders are those? I would be thankfoul for some hints.
Those placeholders are processed by Total.js Framework View Engine.
See the documentaion here https://docs.totaljs.com/latest/en.html#pages~View%20engine