WWW::Mechanize uses autocheck ;) its a nice default with a browser like that

https://github.com/libwww-perl/libwww-perl/issues/258 Pseudo-500 Errors Make Debugging Harder Than It Should Be #258

the rfc does not specify how libraries/apis ought to be implemented. Issue 258 argues the code should be 4xx but those are all server responses too

20+ years ago i learned LWP and about internal error on the first day

500 is the most famous error

In reply to Re: LWP::UserAgent Client-Warning 500 against HTTP standards? (Predates current standards) by Anonymous Monk
in thread LWP::UserAgent Client-Warning 500 against HTTP standards? by Discipulus

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