W3C

List of most popular Bot user agents of W3C

UseragentInfo
P3P Validator
W3C_Validator/1.654
Jigsaw/2.2.5 W3C_CSS_Validator_JFouffa/2.0
W3C_Validator/1.591
W3C_Validator/1.305.2.12 libwww-perl/5.64
Jigsaw/2.3.0 W3C_CSS_Validator_JFouffa/2.0 (See <https://validator.w3.org/services>)
Validator.nu/LV https://validator.w3.org/services
W3CLineMode/5.4.0 libwww/5.x.x
W3C-checklink/4.3 [4.42] libwww-perl/5.805
W3C_Validator/1.432.2.19