I think "the standard" is a bit too strong of a statement.

You're over thinking it :)

Package names are supposed to be capitalized, so yes CamelCase is something generally expected,

Also know as the standard convention

but as for method names I don't see how camelCase is better than CamelCase, both are used, although snake_case is something I see much more often in Perl code.

Do more research :)

You see one used more than the other, so one is the standard camelCase

https://en.wikipedia.org/wiki/Naming_convention_%28programming%29

You see one used more than the other, so one is the standard camelCase

After spending a lot of time on research (maybe even 5 minutes), I couldn't actually remember/find a single module that uses any camel case. So I guess the standard is not to use it ;)

After spending a lot of time on research (maybe even 5 minutes), I couldn't actually remember/find a single module that uses any camel case. So I guess the standard is not to use it ;)

Follow the link provided and you can see a small sample

Also look at the list of core modules, FileHandle, FindBin, I18N::LangTags, Tie::Array, its all the SameCamel