Callout extension
They seem to do find-and-replace, hence many strange behavior. Macana does not do the same parsing as it's quite unintuitive and AST-unfriendly.
Basics
> [!info]+ Title
> Body
> [!danger]
> Danger!
> [!warning]-
> Yay
Escapes
> \[!info]+ Title
> Body
> [!info]\+ Title
> Body
\> [!info]+ Title
> Body
> [!info]+ Title
Body
Edge cases
No whitespace before the marker
>[!info]+ Title
>Body
Phrasing semantics continues from title
> [!info]+ **Bold _Italic
> Body, Italic_ Bold**
Sequential markers
> [!info]+ Title
> [!info]+ Title
> Body
Whitespace in title
> [! info ]+ Title
> Body
[! info ]+ Title Body
Whitespace before exclamation mark
> [ !info]+ Title
> Body
[ !info]+ Title Body
Whitespace before foldable sign
Seriously?
> [!info] + Title
> Body
My guess is they incorrectly re-parse the rest of the first paragraph as block content, like this:
+ Title\nBody
- Title Body
Block quote works fine.
> + Title
> Body
- Title Body