That being said, a conformant extension to CommonMark could adopt the base syntax:
> [!]
> A block not rendered necessarily as a quote but a generic admonition, alert or aside.
It would be up to configuration and stylesheets, which keywords or symbols/emojis would be recognized after the exclamation mark, and how – e.g. color and symbol – this would be rendered.
- reStructured Text (rST) and Docutils have these Admonitions: attention, caution, danger, error, hint, important, note, tip, warning – see Sphinx themes for instance
- AsciiDoc and DocBook support the following Admonitions: note, tip, warning, caution, important
- Bootstrap knows these Alerts: success, danger, warning, info; primary, secondary; light, dark
- Bikeshed, used for W3C specifications, by default recognizes Issue, Advisement, Assertion and Note.
| Symbol | Github | Atlassian | Docusaurus | Obsidian | MDN | Quarto | MS/Microsoft Learn | Google dev | Paligo |
|---|---|---|---|---|---|---|---|---|---|
 |
note | info | note | info, todo | note | note | important | — | notice |
  |
— | — | — | question, help, faq | — | — | — | — | — |
  |
(warning / caution) | (warning) | info | — | — | important | note | caution | important |
 |
warning | note | warning | warning, caution, attention | warning | warning | warning | warning | warning; caution; danger |
   |
caution | warning | — | — | — | — | — | — | — |
   |
— | tip | — | success, check, done | — | — | — | success | — |
   |
— | — | — | failure, fail, missing | — | — | caution | — | — |
    |
important | — | — | — | — | — | — | — | — |
 |
tip | tip | tip | — | — | tip | tip | — | — |
 |
— | — | danger | tip, hint, important | — | — | — | — | — |
  |
— | — | — | note, seealso | — | — | — | — | note |
  |
— | — | — | abstract, summary, tldr | — | — | — | — | — |
 |
— | — | — | danger, error | — | — | — | — | — |
  |
— | — | — | bug | — | — | — | — | — |
 |
— | — | — | example | — | — | — | — | — |
| ” | — | — | — | quote, cite | — | — | — | — | — |
 |
— | — | — | — | — | — | — | — | — |
 |
— | — | — | — | — | — | — | — | — |
 |
— | — | — | — | — | caution | — | — | — |
 |
— | — | — | — | — | — | — | note | — |
  |
— | — | — | — | — | — | — | — | tip |
| — | — | — | — | callout | — | — | — | — |