how can I make "Source Comment" by xml file upload?

Description

I want to make Source Comment data in Source Details at Zanata, but I have no idea how I can write there via xml file upload. below is what we can see at Zanata.

I heard "Flags" is recommended not to touch. I don't know why, just someone said. so I'll avoid to use flags, though I don't know why I should avoid to use still.
anyway, I need to put more data to inform translators what these texts are, so I thought to use Source Comment, but I can't find how to use it at all.
below is what I wrote xml to upload.

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Reporter

Evil Dragon

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