A bug tracker ago, @Aklapper set up a cron job to inform him of changes in the Bugzilla taxonomy. On wikitech-l, I proposed to (additionally) dump the taxonomy regularly to a wiki so that normal users can watch changes as well and was asked to file an enhancement request.
https://phabricator.wikimedia.org/project/query/all/ looks like a list of all projects and is probably queriable via an API as well. For the target on the wiki side, there is https://www.mediawiki.org/wiki/Phabricator/Projects but its purpose is unclear.
Cf. T833
https://github.com/wikimedia/labs-tools-wikibugs2/blob/master/taxonomy.py writes https://www.mediawiki.org/wiki/Phabricator/Projects/Test
but needs to be set up as a weekly cron job, and needs to be adapted to a better page, e.g. just /Projects.