W3C is a software developer who develops bots. See below the software that is developed by W3C.

By the way, maybe you are looking for W3C user agents?

Bots:

• Jigsaw CSS Validator
• Jigsaw_W3C_CSS_Validator
• P3P Validator
• Validator.nu/LV
• W3C-checklink
• W3C I18n Checker
• W3C Unicorn
• W3C_Validator
• W3CLineMode