The .csb file type is mostly found in files that are source/ script/ data files used in running other files critical to Corel Photo- Paint application.
Corel Photo- Paint is a raster graphics editor that can open and convert vector formats from CorelDraw and Adobe Illustrator and can open other formats, including PNG, JPG and GIF files — as well as competing photo editor formats from Photoshop, GIMP and Paint Shop Pro. The program also supports plug-in functionality, including those developed for Adobe Photoshop  and Paint Shop Pro.
CSB file is a Corel Binary Script. Corel Script is a utility which allows Corel software to run the macro-like programs written in the Corel Script language. Without the .csb script, Corel applications, especially, Corel Photo- Paint will not work as intended.
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