In future releases I suggest the wording of around the Configuration > Upload > Add Video Mechanism (Fetch Link Only) be more clear... it is confusing and ambiguous and takes a few minutes to decipher... there are too many negatives or something as well as too many labels for what one is selecting yes/no.

any specific suggestion?

Perhaps renaming the "Add Video Mechanism (Fetch Link Only) " option, something like "Link video (instead of uploading)".

I would suggest the comment to be something like:

'If "yes" is selected here, video upload and download cannot take place. Videos on the site are linked from other supported platforms.'

The next sentence in the comments, "If NO CONVERTER in place, you must enable this." is unclear... does it mean if another setting called Converter is disabled, the link video (fetch link video) must be set as "yes"?

If that is the case perhaps it could be worded as: 'If there are no video converters set-up (see Config > Converters), then Link video must be set to "yes".'

Hope this helps.

ok, how about
Add Video Mechanism:
instead of yes or no
we can have "link only" or "upload / link"

what do you think?

That's more clear. Consider also editing the note and comments associated with the setting, as appropriate.

will do ... will be changed next version