I want to use the contents of the tiddler $:/config/NewJournal/Tags inside a filter with tag operator.
Currently, it only has one string Journal. But it can get more entries, like Journal [[example tag]]
Things that I have tried
and failed.
I expected following attempts to work at least when {{$:/config/NewJournal/Tags}} evaluated to a single string i.e. Journal. But I was wrong.
One
{{$:/config/NewJournal/Tags}}
I expected translusion to work inside the filter.
<$list filter="[tag[{{$:/config/NewJournal/Tags}}]]" />
Failed 
Two
I noticed that list operator can show the content this way
<$list filter="[list[$:/config/NewJournal/Tags!!text]]" />
So I tried same syntax with tag operator
<$list filter="[tag[$:/config/NewJournal/Tags!!text]]" />
Failed. 
Three
<$vars example1="$:/config/NewJournal/Tags">
<$list filter="[tag<example1>]" variable="ignore">
Failed. 