A portable document starts with a small stated dialect. MarkdownPreview keeps core syntax and disables tables, task lists and automatic hard breaks.
Blank lines separate blocks
Use a blank line between paragraphs and around lists or fenced code when the boundary matters.
Link destinations stay explicit
HTTP, HTTPS, mailto and same-page anchors can remain active; other schemes are shown without a clickable destination.
The final platform may differ
GitHub, chat systems and static-site tools add different extensions. Verify the final document there too.