Files starting with unserscore are built

[manuelmeurer]

The readme says

If both the hash key and the hash value are directories instead of files, it configures a directory to directory compliation, which compiles all public Sass files whose filenames do not start with underscore (_).

I am using this configuration

Rails.application.config.dartsass.builds = {
  "." => "."
}

Still, when I run dartsass:build, Sass partials are compiled:

Writing subfolder/_index-adcce2b423a46ddd09284eee05d1033fa794f95a.scss