MediaWiki:Val form note

Hint: Merging your data means that for the article revision you select, all options where you have specified no opinion will be set to the value and comment of the most recent revision for which you have expressed an opinion. For example, if you want to change a single option for a newer revision, but also keep your other settings for this article in this revision, just select which option you intend to change, and merging will fill in the other options with your previous settings.