This article explains what ABR files are, how to open them on your computer, and how to convert a PNG or JPG file to view the brush as a regular image.
Download .abr brush files and import them into Adobe Photoshop
A file with the ABR file extension is a Photoshop Brush file that stores information about the shape and texture of one or more brushes. They are used through Photoshop's Brush tool and are saved by default to the program's installation folder under …/Presets/Brushes/.
You can open a brush in Photoshop using the Brush tool. See our How to Install Brushes in Adobe Photoshop guide if you need help.
If that method doesn't work, some versions of Photoshop allow you to import brushes through Edit > Presets > Preset Manager. Choose Brushes as the preset type, and then select Load to locate the ABR file.