gnu-screen was already set up as a synonym of screen. That means that anyone attempting to tag with gnu-screen would end up with screen.
I have now reversed the synonym so anyone tagging with screen will get gnu-screen instead. I've also retagged the questions you linked to.
I don't recall seeing a question about LVM1 on this site. It was already obsolete by the time this site started. So for all intents and purposes lvm and lvm2 are currently equivalent.
I favor merging them, and making lvm the main tag. (Only moderators can do this.)
If an incompatible LVM3 comes along, we can start using lvm3 for it. Then make lvm2 the main ...
The tag list isn't fixed -- anyone with enough reputation can create new tags, but they need to be attached to a question. I added lubuntu to a couple that looked like they could use it. However, since Lubuntu is an official Ubuntu distribution, most questions about it are probably going to be on Ask Ubuntu, a related Stack Exchange site focused on Ubuntu-...
STREAMS is rather obscure. Additionally, STREAMS is normally written all-uppercase but tag names are in lowercase. So it's understandable that people see streams and don't realize that it refers to some concept they don't know about. (Tag wiki? Who reads tag wikis?)
I don't think there's an ideal solution but renaming the tag should help. How about sysv-...
Posts with /distro-version tags aren't significantly more in need of editing than average. There are plenty of /distro tags that shouldn't have that tag, too. Having decided that having the version in the tag is useless, changing /distro-version to /distro does not remove any information. So there is no advantage to a manual cleanup. There are obvious ...
Several upvotes but no answer?
I consider them duplicate. Apart from that IMHO tag names should be clear. Knowingly having these two for different purposes would most probably confuse a lot of people.
But I would not consider it useful to create bash-builtin, csh-builtin and so on. What is the advantage of bash-builtin vs bash shell-builtin? We have fsck, ...
google-chrome was just an oversight; I merged it into chrome since chrome had considerably more instances, so now all three are grouped together. We normally only make synonyms if there's a history of people using both instances; tag and tags aren't synonyms because neither exists
I have merged wheezy into debian, the various fedoras into fedora, centos6 and centos7 into centos and sles11 into sles.
I can't find any other version-specific tags so I think that's the lot of them. If anyone finds new ones, please leave me a comment here, or flag the relevant post for mod attention and point out the tag.
/cdrom would be a better tag than /data-cd, I think. Typing cd would pop it up as an autocompletion, so people would discover it automatically.
Or /optical-disc would cover data dvds and data blu-rays, too. We don't need or want different tags for those, do we? Tags that are too specific mean too many tags.