The tags query module has a tgprop parameter to specify which properties of the tag should be returned. One of these properties was 'name', but the name was always included in the response regardless of whether this property was included in tgprop.
Since most uses aren't specifying 'name' but we can assume clients are depending on the name being included (since there's otherwise no way to identify which tag is which), we've removed the nonfunctional 'name' as a valid option for tgprop. This will result in a warning that 'name' is not a valid value for tgprop for those few clients that are specifying 'name' there.
This change will not affect the functionality of any clients unless the new warning somehow breaks them. It should be deployed to WMF wikis with 1.31.0-wmf.18 or later. Clients can safely stop specifying 'name' in tgprop immediately, though, since it doesn't do anything.