Sidenotes could have arbitrary markup:

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foo^[ *bar* ]
.
xxx
.



test inline in middle of paragraph:

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foo^[ bar ]baz
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xxx
.



test multiple paragraphs

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foo^[ bar ]baz

this is the second paragraph
.
xxx
.



Also, sidenotes can be nested:

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foo^[the bar is open^[there's no COVID in this test] and the drinks are free]
.
xxx
.


And sidenotes can contain regular footnote references too, obviously:

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foo^[the bar is open[^bar] and the drinks are free]

[^bar]: there's no COVID in this test
.
xxx
.


You can also direct *any* footnote to become a sidenote, section note or endnote using the `>`, '=' and `:` flags respectively:

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foo^[=the bar is open[^bar] and this has become a section note^[:while this inline note has been flagged[^buzz] as endnote too!]]

[^bar]:: this has become an endnote

[^buzz]:> this has become an aside^[>that's another name for a *sidenote*, as is this one -- with explicit (superfluous[^boss]?!) flag...]

[^boss]:= Well, `^[>...]` may look superfluous at first glance, but we MAY change behaviour one day and have the `options.modeOverride` *only override non-explicitly flagged footnotes*.
.
xxx
.