* support variable substitution, from https://github.com/yt-dlp/yt-dlp/pull/#521 etc, thanks ChillingPepper, Grub4k, pukkandan * improve escape handling, from https://github.com/yt-dlp/yt-dlp/pull/#521 thanks Grub4k * support template strings from https://github.com/yt-dlp/yt-dlp/pull/6623 thanks Grub4k * add limited `!` evaluation (eg, !!0 -> false, see tests)