https://forum.plantuml.net/12480/new-line-in-table-built-with-variables-broken-from-1-2020-20?show=12547#c12547
@startuml
!$var=" aaa \n bbb \n <u:blue>ccc \n <color:green>ddd <U+000A> eee"

node "$var" as a

node b [
$var
on multi-line context
]

node c [
<code>
$var
</code>
]
@enduml
