The default for suffix for configuration files, which might be used by other frameworks etc. and the contents of the Mojolicious::Plugin::Config files are actually Perl.
Mojolicious::Plugin::Config is quite powerful so you can just configure it to respect your new extension.
So in order to differentiate and get my text editor to enforce a distinction for syntax highlighting, I renamed my configuration file to .pconfindicating Perl formatted configuration.
See examples below, for how to configure Mojolicious::Plugin::Config to respect the new extension - do note the dot/period . is not specified.
plugin Config => {ext => 'pconf'};my $config = $self->plugin('Config', ext => 'pconf');