Which Markdown processors preserve ISO‑8601 timestamps without timezone conversion?

Markdown's CommonMark specification does not define any syntax for dates, times, or timezone offsets, leaving timestamp handling entirely to surrounding tools. Static-site generators such as Jekyll and Hugo parse ISO‑8601 strings in front matter, while general-purpose renderers like pandoc and markdown‑it typically pass date literals through unchanged. This inconsistency means a document authored with a regional timestamp may display differently depending on the publishing pipeline. The goal is to understand which processors guarantee preservation of the original offset and which apply implicit conversion to UTC or the server's local zone.

1. Does GitHub Flavored Markdown alter inline ISO‑8601 strings during HTML rendering?
2. Which static-site generators perform automatic timezone normalization on front-matter dates?
3. Can a portable Markdown document reliably convey a regional time without embedding explicit offset metadata?