Document x_deprecated field?

[robrwo]

See http://neilb.org/2015/01/17/deprecated-metadata.html and https://metacpan.org/pod/Dist::Zilla::Plugin::Deprecated

[Leont]

A general document on Meta extensions would be useful (though that doesn't necessarily have to be in this distributions. Something like CPAN::Meta::X I suppse, but maintained closer to the toolchain.

[robrwo]

A general document on Meta extensions would be useful (though that doesn't necessarily have to be in this distributions. Something like CPAN::Meta::X I suppse, but maintained closer to the toolchain.

CPAN::Meta::Extensions, which would match what is done with PSGI::Extensions. CPAN::Meta::X sounds a bit like it has to do with X-Windows for X/Twitter.