MariaDB [(none)]> SELECT dbname FROM meta_p.wiki WHERE url LIKE 'https://jp.wikipedia.org'; Empty set (0.00 sec)
This breaks tools that rely on this table, such as: https://xtools.wmflabs.org/adminstats?project=jp.wikipedia.org
There may be other wikis missing. With SELECT COUNT(*) FROM meta_p.wiki I see there are 874 wikis configured, but using the API there are 911 total, but perhaps closed and private wikis are intentionally omitted.
Japanese Wikipedia is jawiki, not jpwiki. https://xtools.wmflabs.org/adminstats/ja.wikipedia.org works for me.
Ah! I see, https://jp.wikipedia.org redirects to ja. So I suppose there is no issue there with meta_p.wiki, then =p
I ended up there from en:Template:User articles created (日本語), which has a working link to jp.wikipedia.org, but the XTools link is broken. I suppose we just need to change any links to jp to point to ja, as it appears even through the Sitematrix API there is no record of jp.wikipedia.org, and hence I think it's OK if XTools does not recognize it.
Closing. Sorry for the noise!