Thanks! This seems like a generic angular routing.
“For example if we have a html in the directory src/static-pages/page1.html, by default if you add that path to the assets section of your angular.json, it will exist at the route http://hostname/static-pages/page1.html. Angular allows you to change the resolve path for this asset to be whatever you want by providing a few extra pieces of information into the assets section when referencing your static html or other asset.”
Source : https://stackoverflow.com/questions/53416871/routing-to-static-html-page-in-angular-6