I can't edit my answer to https://electronics.stackexchange.com/a/4341/142 to add attribution or fix the rotted links, and I can't flag the question for this problem, either; there is no Flag link, only a Share link. So I'm posting here. Can you unlock the post?
Reasons you should be able to flag a locked question:
- It may have been locked by mistake and you want to argue that it should be re-opened.
- The site's rules could have been discussed and changed so that the lock is no longer appropriate
- The site's rules could have been discussed and changed so that the locked question should now be completely deleted.
- The question/answer could contain links that have since been redirected to spam or inappropriate content.
Reasons you should be able to edit a locked question:
- The question/answer could contain links that have since rotted or been hijacked and need to be updated.
- The answers contain external images/content without attribution and it needs to be added.
There are probably other reasons, too.
A question is locked because:
it has historical significance, but it is not considered a good, on-topic question for this site
This means that the question is still intended to be viewed by site visitors. (Otherwise it would have been deleted.)
For instance, a question on SO of "What's your favorite text editor" would have been fine in the first iteration of the site, but later decided to be inappropriate because it's too opinion based. The question is locked, because the content is still valuable to visitors, but not the kind of question that should be asked in the future. But the links to the text editors rot as the internet changes, so it should be possible to edit them to correct the links.
Can't edit or flag a locked post
Exactly. That's what "locked" means. The messsage in the box that indicates the question is locked says in part "This question and its answers are frozen and cannot be changed.". This is really quite clear.
Put another way, you're not supposed to be able to edit anything. This is a dead question that was only left around for historical significance, again, just like the message says. It really shouldn't be here in the first place. We certainly don't want people editing it and bumping it to the top of active list.