You can use this widget from the marketplace: https://marketplace.mendix.com/link/component/115773
Or you can create a simple javascript action to be used in a nanoflow:
const title = "some new page title";
document.title = title;
I believe this is hard-coded in mxui.js, so it won’t be easy to change.
If you change it in mxui.js, this is part of the Mendix installation (not the app) and so it will be changed for all apps created with that version
The place to change is:
f.after(this._contentForm, "onNavigation", (()=>{
const t = e.profile + " - " + n._contentForm.title;