It appears that to the Catalyst community YAML isn’t the best config file format any longer as they’ve chosen to switch in favor of Config::General – which defaults to the "apache config format"
From Config::General’s POD:
The format of config files supported by Config::General is inspired by the well known apache config format, in fact, this module is 100% compatible to apache configs, but you can also just use simple name/value pairs in your config files.
Catalyst::Plugin::DebugCookie even provides the updated configuration style in it’s POD:
The following command can be used to dump an existing Catalyst app’s config into an Apache style conf file. You’ll definitely have to edit the resulting file, but at least it’s a start.
perl -Ilib -e ‘use MyApp; use Config::General; Config::General→new→save_file(“myapp.conf”, MyApp→config);’