My immediate take on this is:

[tag:version-number] is only used once, and seems relevant in that context.

[tag:previous-versions] refers to functionality provided by Windows to roll-back files; this tag is valid.

*[tag:versions]* is already a synonym of [tag:version], so doesn't really exist.

[tag:version] (and so *[tag:versions]*), along with [tag:versioning], should *probably* all be synonyms to either [tag:version-number] or [tag:version-control], which are much more explicit. However, there's going to be a manual retagging job to be done here as I suspect many of the current questions are misusing them, but many will need saving.