File created by Edge Reflow, a responsive web design application; contains your Reflow project settings such as page layout and styling data; examples of contained data include margin size, typography settings, background, and borders.

To create a RFLW file, simply select File → Save As, name your project, choose your save location, then click Save. You now have a project folder in your save location. The folder contains your RFLW file along with an "assets" folder holding other files such as a .CSS file, .HTML file, and an "img" folder containing any images from your project.