There are many problems with the #Database tag. It is confusing, and many people do not differenciate it from MediaWiki-libs-Rdbms. I want to rename #Database to DBA, (we can keep the alias) and make sure that we differenciate between tasks involving mediawiki code related to relational storage (done mostly by mediawiki hackers), and work on WMF MySQLs (done mostly by WMF operators).
In addition, schema changes are not as easy to be done as before. I think Schema-change can continue existing for proposed changes in mediawiki infrastructure, but we need another project to mark "this schema change is final, apply it to WMF infrastructure now". Thus I propose #Blocked-by-schema-change, with a similar spirit than Blocked-on-Operations. I think DBA should be a subcomponent (blue) (or a team?). Blocked-on-Operations should be a yellow or red tag.
The rationale and workflow has been documented on https://wikitech.wikimedia.org/wiki/Schema_changes/Coordination_proposal and many people has already agreed to follow it, unblocking many pending changes. I want to officialize it.