Did you know that Delphi allows to add associated files to existing units? For example you can add .html and .css files to a unit, so that they are shown in the project manager. Here is a screenshot:
This can be done by adding the following line to the .dpr file
program Project1;
uses
Vcl.Forms,
Unit1 in 'Unit1.pas' {Form1: TForm} {*.html} {*.css};
...
TMS Web Core uses this feature in order to add an .html file to a web form and an optional .css file as you can see in the screenshot.
