Adding specific content to xhtml output

[Pavel Sanda]

On Thu, Apr 30, 2020 at 10:51:52AM -0400, Richard Kimberly Heck wrote:
> > GUI-wise I'd propose a checkable list of output formats in another
> > QTreeWidget. This would translate into a comma-separated list of output
> > formats in the params.
> 
> To address Pavel's concern about user-defined formats, we have access to
> that info, though we might need some flag to indicate what a 'real'
> output format is. Otherwise, we end up with too many listed.

Yes, we would need some sort of flag to know what we want to list. 
Looks as an overkill to me, but don't have strong opinion about it.

Pavel