3:45 AM
Removed tags (from the most recent ones): main, meta.
Created tags (from the most recent ones): main, meta.
Recent suggested edits on tag-infos: main, meta.
Recent tag-info edits: main, meta.
Orphaned tag-wikis: main, meta.

4 hours later…
7:24 AM
Only today I noticed that (by mistake) I wrote "blacklisted" instead of "deprecated" in the title of the question on meta: What to do with the synonyms for the deprecated tags?
6

Recently, the following tag synonyms were created by a MathOveflow moderator: abstract-algebra $\to$ ra.rings-and-algebras, geometry $\to$ mg.metric-geometry and discrete-mathematics $\to$ co.combinatorics. You can see the new synonyms in the list of tag synonyms (Wayback Machine). The three tags...

12 hours later…
7:42 PM
> It is possible to use various SEDE queries to search among the questions which have the deprecated tags. For example, this query returns the questions which have the given tag.**
> And you can add various further criteria to the query. (Although it is definitely less comfortable than searching directly on the site.)
> **In SEDE you can see the status when the database was last updated, which was before creating the synonym. (It is updated once a week.) As far as I can tell, the questions will be still visible in the SEDE queries even after the next update of SEDE. (Unless the moderators also merge the tags.)
> You can check some similar instances - the tags which were made synonyms without merging - on Mathematics, such as span or conditional-probability.
As I have said that one can add various further criteria to the query, perhaps I could add at least some simple examples.
As mentioned above, SEDE query can return questions with a specific tag, and here is the same ordered by last activity.
I can search for questions in a given tag which contain a specific word or phrase. The same ordered by last activity.
I can search for questions with some combination of tags, for example, abstract-algebra and gr.group-theory.
Or I can exclude some tag - for example, questions tagged abstract-algebra without gr.group-theory.