"It is not possible to filter by strings containing double quotations marks. This is a limitation of the feature." - I think that there was the workaround with $char(34)
e.g.
I am not sure if the filter syntax is really described correctly.
Most syntax examples start with <field> ...
(fascinatingly with some kind of metasyntax...)
but I think that this not really just a <field> as there are filter examples like
where the scripting part at the front is not really a <field>
I would think that this is a "generating format string" enclosed in double quotation marks.