Method is_beta

rust/src/lib.rs:803–805

(&self, browser_version: &str)

    }

    fn is_beta(&self, browser_version: &str) -> bool {
        browser_version.eq_ignore_ascii_case(BETA)
    }

    fn is_browser_version_dev(&self) -> bool {
        self.is_dev(self.get_browser_version())