The downgrade tag has the following description:
This tag refers to the process of replacing a particular system with an older version of the same system
This tag does not really add useful information to questions with it, and you can't be an expert in "downgrading" in general.
I think the downgrade tag should be burninated. Let's go through the formal burnination criteria:
Does it describe the contents of the questions to which it is applied? and is it unambiguous?
No. Whilst all these questions are vaguely about downgrading something, the thing being downgraded is not the same in all cases.
Is the concept described even on-topic for the site?
No, since it's not something that is strictly programming-related.
Does the tag add any meaningful information to the post?
No. Since anything can be downgraded, this tag does not add any meaningful information to the post.
Does it mean the same thing in all common contexts?
Not really. Whilst the questions are all about downgrading in general, they range from downgrading frameworks to downgrading operating systems.