On Wikidata, we want to remove the changetags right from most users, and only give it to sysops, so that ordinary users cannot add and remove tags on arbitrary edits or log actions. Users should keep the applychangetags right, which will allow them to add tags on their own edits and log actions as they are made. Well-written user scripts and gadgets should use the tags parameter to the various APIs (T229917), rather than adding tags with action=tag separately, which means that the ability to modify tags after the fact is mainly abused for vandalism (typical example).
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