Customize / Override ArcanistConfiguration

It seems arcanist_configuration has been removed - https://secure.phabricator.com/T13203

But our company has been customizing the diff and land workflows by overriding ArcanistConfiguration.
What is the alternative approach without arcanist_configuration field?

Also the official documentation still says it’s supported.
https://secure.phabricator.com/book/arcanist/class/ArcanistConfiguration/

Thanks

See https://discourse.phabricator-community.org/t/how-can-you-customize-diff-and-land-without-arcanist-configuration/3853/2.

The documentation will be updated after https://secure.phabricator.com/T13490 resolves.