From the toolbar at the top, you can switch to Developer Mode by clicking
Mode Switching Button.
You can check and change HTML ID here. There is a check box for Export HTML ID. At the
Project panel (IUEditor Menu Bar > Preference), you can set the options from Export HTML ID Option. (Offered options: Always include/ Optimization & customization)
You can write back-end, custom css, script code. The tab composition differs between widget and project type.