My comment in PR included

> BTW - would it be useful to notify about retagging such as shop=guns to shop=gun before they happen (or after they happen?). It was suggested to me in https://www.openstreetmap.org/changeset/148979715 that doing it would be useful but I am not entirely sure about it.

> Or would it be useful in cases where specific tag value is reported as supported, and not useful when key in general is supported?


and reply was

> The entry is for shop=<anything> . A change from 'gun' to 'guns' is not relevant.


as expected given that declared support was not for specifically shop=guns but for shop=* (with exception for shop=no, as described in freeform text)