Function resolve_import_source 

pub fn resolve_import_source(
    browser: &str,
    domains: &[String],
    platform: &str,
    home_dir: &Path,
    environment: &Environment,
    run_command: Option<&RunCommand>,
) -> Result<ImportSource>

Pick the source browser for an import.

A default/auto request scoped to domains uses the system default browser when it holds cookies for them and otherwise falls back to the installed browser profile holding the most, so “import my github.com sign-in” works whichever browser has it. Only names and counts are read (see list_cookie_sources), never cookie values.