• Reference & Education, Language
• EX3 file structure
• June 18, 2026

An EX3 file is a file with the `.ex3` file extension, meaning the filename ends in something like `sample.ex3`. A file extension is the label at the end of a filename that gives Windows or another operating system a clue about what kind of file it may be and which program may be able to open it. However, the extension …